Wednesday, November 30, 2011

Explanation of Composite Materials

I just stumbled across this useful information sheet on loads of different composite materials and tools. It seems to be aimed at aircraft (full and model) builders but included carbon,e-glass, s-glass and various resins.  It has good laymans explanations of the features of the product ( e.g the weave pattern, vac bagging, different reinforcements) and great info on when and why to use some of the things!

New Brokite Video

Its been a while since I checked out Brokites site so have just caught up on the fact that they have added 2 more tech videos to their web-site. One on how they work with ABS plastic and the other is how they make their inserts.

These guys have simplicity and sophistication down pat!

Monday, November 28, 2011

Cut core and poured rails

Today was my first attempt at using a router to cut the cores and I was very very happy with the way it turned out. A small victory but a victory none the less.

Routed around the top and bottom templates using with the templates on top. I used Deans tip of putting double sided tape down (under the template and under the board) and no clamping was needed. I used a inverted flush trim bit which has the bearing at the top and cut all the way through.

Instead of routing a channel for the rails I cut all the way through the core. My top deck extends out on to the rails and so it need the poured rails to be flush with the top surface. To create the channel for pouring the rails I put packing tape on the underside of the board to create the channel.

I poured the rails as well and fell into a trap for young players - forgot to level the table properly and because I didn't mix and q-cell in the resin ( going for clear rails) it very quickly flowed to one corner at the expense of the others.  This was quick to remedy and so its curing away as we speak.

The rail channel is 9.5mm x 6mm x 3.16m and used about 240gm of resin (c. 120 mls)

Sunday, November 27, 2011

Paper graphics

When I was gluing the woodplanks together I used some of the left over resin to see whether it would cause the inkjet printed graphics to run. I'm happy to say it did not.

I took a few picture but you can't see much from them because the font I used (old type-writter) already looks smudged and the camera had trouble focusing properly so the blurred images make it look like is has run. But, I assure you it did not. The pixelation that was visible right off the printer was still there, there was no obvious running of spreading of the inks.

I was using standard inkjet ink (bought from Coles in fact) on 80 gms printer paper. The paper became translucent but no were near transparet. Thin stock (tissue paper or rice paper), I've read, is the way to go.

I am going to try on thinner stock to see if it makes any difference but I am quietly confident it won't.

Just for completeness here's a few of the snaps ( I promise in real life its not running)
The logo in the free font 'Old Typewriter'
Close up of the underside - although the font has rough edges the edges remain well defined.  
The red dot - the red halo around it is due to light and poor focus of camera.

Thursday, November 24, 2011

Starting on the core at last!!!!

After many distractions, a couple of other projects and a fair bit of time sourcing materials for the boards I finally started on my first wood core. Only a baby step but it feels good to be  moving forward.

I decided to build the core up our of 6mmx100mm Paulownina planks instead of starting with a thicker core and cutting and routing it into shape. I don't have particularly good tools to work with so for this board at least I'm trying to minimise the work.

Tonight I stuck the planks together (told you it was a small step!). I had intended to slice them into 50mm widths and mix them up to average out the weakness in the wood by shuffling the planks but the strip cutter that I used for balsa previously wasn't up to the job of cutting the much denser Paulownia. So instead I decided just to work with what I've got until I can put together a small table saw to make sure I mill the planks perfectly.

So, the first thing I did was to squeeze the planks together and put masking tape on one side of the board. The idea is to use the tape as a hinge to make it easier to get the epoxy into the join and stop the resin flowing away.

Tape hinges to retain glue and apply some initial pressure to the join.

Tape hinge made it easy to 'wipe' glue along the vertical surface and have it run into the join before closing the join to squeeze the resin around.

Found an extra use for the angle iron of the rocker table. With the angle iron piece used to support the center jig I squeezed the planks tightly together. I put the tool box on top so that when I tightened the ratchet strap it put pressure down on the MDF board templates its sitting on at the same time as the strap squeezes the planks together and so that the freshly glued joints where nice and tight.

Next step is to cut out the layers using the router. First time using one so should be interesting!!!

Saturday, November 19, 2011

Check out Dean's progress on his new board

Dean in WA has got a great set up that is well worth checking out. He's a perpetual innovator!

I love the rocker table idea. He basically took a plaster mould of an existing board and tada!!! Instant rocker table which can be placed completely inside a sturdy vacuum bag - no clamping, no jigs. Brilliant!!!! He' used 1mm vinyl for the vac bag.

I've been thinking that it would be a lot easier with my set up to lay the board up with the acrylic part of the rocker table surface flat. Put the whole thing in a vac bag rather than fuck around with tacky tape and then clamp it down. I'm thinking that the vinyl would be strong enough to take the pressure of the jigs clamping down on it. Provided that there was plenty of bleeder material to soak up the excess resin then the bag would be reusable.

In the video by Fibre and Foam ( search youtube for it) her used vinyl for the vac bag too and it worked fine. However, he put the vinyl directly onto the board surface without breather/bleeder material and it left a ripple effect on the surface of the board because without the breather material, once it comes in contact with the resin, the resin is sticky enough that its nearly impossible to apply enough force to stretch the surface tight.

Friday, November 18, 2011

Rocker table upgrade

First things first, I had to get my rocker table sorted because parts of the last one I used were cut up in the course of the camper van fit out I was working. So this was a good chance to customise the table a bit to make it easier to use and stronger.

I stuck with the original Brokite style design because it just has so many benefits and that the setup that BoardOff's jigs are designed around.

The setup is two matching steel frames one each for the top and the bottom and made out of 40x40x3 mm angle iron. Then use middle and out rocker / concave jigs straight out of BoardOff and clamp easily to the angle iron frames. The top and bottom jigs then come together to bend the rocker table surface over the center jig to get the right compound curves into the table surface (which going to be the same 4mm ply and 4mm acrylic as I used previously. I checked with the plastic supplier I bought it from and they said that the plastic won't deform until it reaches 100 degrees so 50 degrees is no problem. Even if it was a problem, the plastic is supported on the 4mm ply.

Although the table's not tweakable like tables with individual slats that adjust, changing the set up is just a mater of cutting out the new jigs from scrap wood (MDF) and it seems there are no shortage of old cupboard doors thrown out on the pavement that suit the purpose nicely.

So here's the revised table with all the jigs clamped in place with a single G-clamp for each.

I was lucky enough to find a single bed frame at our local St. Vincent de Paul op shop. It has casters and the fold out legs you can see on the bottom section. Its handy for a number of reasons including being at a better working height and will make it easy to place heat lamps close to the work so that I can post cure it at 50 degrees.

The bed slats are pretty solid and I think that they should solid enough to support the load of the center jig without bending.

For the top frame I bought 40x40x3 mm angle iron from Edcon steel which cost about $17 for all c. 6 m of it (compared to $25 for 2m from bunnings). I welded it together and also welded some long bolts in each corner top and bottom to be used to pull the frames together.

My idea is to use ratchet straps around the bolts to clamp it together. The ratchets for both sides can be done simultaneously to help make the clamping action uniform so that it doesn't spill the rocker table surface out one side like it did last time.

The snap below shows the center jig. You can see it in the shadow but the center jig is clamped to a piece of angle iron. This will help keep it straight when its loaded up and also distributes the load across all the bed base slats which should limit bending further.

Next step is to work out how to turn it into an oven. Dean in WA cure his board using standard 100W bulbs. He said that its important to have a fan circulating the hot air and also to make sure you're measuring the temperature at the board surface and not in the top of the oven where the hot air will collect. I also spoke to Dave who runs the engineering show at maxi yacht building facility and he said they put temperature sensors right inside the work so they get exact temp measurements. I'm still working through some ideas for this one.

After that its on to doing the actual board!! Yeah fucking ha!!!

Thursday, November 17, 2011

Board graphics just arrived

I've just received the graphics that I'm going to encapsulate in the board and it looks awesome!
Printed on 135 x 41 cm SILK (although it feels like a synthetic material so maybe SILK is a working name for it. Have asked for some details).

StykerMedia ( on the Gold Coast in Queensland Australia supply prints like these for surfboard graphics so they've got experience with these being encapsulated in epoxy. $25 per print (cheaper for larger quantities) + delivery makes it about half the prince of dye sublimated PBT and has the advantage that you can actual find a supplier of it!!!!

The image is a photoshoped version of The Great Wave off Kanagawa which is one of the series 36 Views of Mount Fuji by Japanese artist Hosukai. I found it on google images (using the 'large' search option) and added the sky because the original is a grey and dull.

Colours came out brilliantly, 300dpi resolution, no pixelation (which was a concern as I pulled the image from the web and put it into a pdf). Website says that wets out completely clear. My plan is to use 2 layers of glass and encapsulate it in between. Will most likely use 4 oz s-glass as the last layer as its apparently much better for impact resistance due to the 30% greater strength and 3 times the strain to breaking (3.5% compared to 1% for e-glass)

Close up of the SILK material.

Flysurfer board making video

After a friend of mine broke the news to me that he had just bought a Flysurfer Speed 3 15m kite I checked out their website and came across an arty video of the board making facilities.

Note the appearance of that damn pneumatic press.. How do they do it without getting dry spots??

Couple of interesting things:

i) 90 psi pneumatic press
ii) wet layup and not pre-preg like I thought might have been used for the high pressure clamping
iii) screen printing the topsheet and not dye-sublimation printing like the other production board companies info that I've come across
iv) plastic tips covering most of the end of the boards - according to the commentary its to give the tip loads of flex 'for rider comfort and control'..
v) appear to be using superglue to stick the rails on. I remember using a gel type super glue one when making a model aeroplane. It helped prevent the glue being sucked into the wood and away from the join and also helped it bridge any gaps which the normal superglue (cyano-acrylics) would drip through.
vi) use a heat gun to heat treat the rails or maybe it is to accelerate the curing of the glue they are using.

Check out the video on the light wind board. Asymmetrical outline and negative heal-side rail. In the video they say that the negative rail helps take some of the pressure of the rail and allows you to put it over the tip and tail. Presumable to allow you to get the fins deeper in the water. 'Help you ride the fins more than the rails'... Why is this a good thing?

Sunday, November 13, 2011

Very, very cheap source for fins

I came across this vendor on e-Bay who sell fins v. cheaply. Their website is good and the video of the fin strength test is impressive. They are polycarbonate reinforced with fibreglass.

I'm going to order a few of the 2" fins and see how they go. They are listed on ebay at $22+$4 shipping for 4 - about 1/3 of the price of the cheapest fins I can get in Oz.

They also mention that the top and bottom sheet material they use is Dupont's Crastin® PBT. At least this is one lead to locate an AU distributor. Unforetunately they won't sell you printed sheets of PBT for DIY'ing

UPDATE: Fins on their way

Update 2: These guys also sell foot pads, strap and grab handles plus for a small setup fee will print your own logo on any of these accessories. No minimum order. Will keep you updated when I get hold of them. The ones below were $57 USD + postage ( $17 to Australia). Dimensions for the pads are on the website.

Update 3: All arrive very swiftly - 1 week ( express and 1.5 week regular post from taiwan!)

Logo for boards

I've been having a bit of fun trying to come up with a brand name for the boards and have settled on Dart Boards. Here's the logo.

The idea is to change the tag line in the middle each time to add something unique or funny and to include good quality artistic graphics each time (hence the 'art' part).

Board 3 Templates

It's a happy coincidence that each time I start a new board council clean day comes along and provides all the wood I need for the rocker table jigs and this time for the board templates.

Despite thinking about different ways to make the table adjustable, using fixed rocker and concave jigs that are cut from mdf and building a Brokite style clamp just proves to be so easy. It's easy to get the material, easy to make sure you have a symmetrical setup and is reusable. Also, because the plan is to post-cure the epoxy at 50 C (the recommended temp for the R180 epoxy from FGI that I'm using) then you have 2 of the sides of the 'oven' in place provided by the outer jigs.

So first step after finalizing the design in BoardOff is to trace and cut the jigs and outline templates.

Rocker table jigs cut from 15mm MDF using BoardOff Rocker/Concave profiles
Upper and lower deck templates. Also 15 mm MDF (black paint is just to seal it from the elements)

Thursday, November 3, 2011

Board Graphics Options

Well been out of action for a while doing a fit out our van ( which came out sweet). Now that project is behind me I'm getting the board building happening again.

I've been looking around at different options for graphics and thought I'd share the few things I've found out.

The most common production board approach is to use a high density, abrasion resist plastic film with the graphics printed on the underside using dye sublimation printing. The typical film material its printed on to is PBT or UHMWPE (ulta high molecular weight polyethylene) which has product names like Durasurf or PTex and is commonly used as a bottom sheet for snow boards. Problem is it seems to be near impossible to source in Australia. in the US sell it and will print your graphics for $50 but the shipping cost is about $150!!

Dye sublimation printing can be used to print onto othe synthetic fabrics and is used to print promotional material ( flags, banners etc) on polyesther fabrics. This might be an option if the polyesther is light weight with a big enough weave for the resin permiate. A local printer I spoke to suggested giving Trilobal Polyesther, commonly used in printing flags, a go. He said the weave is open and it holds a print well. Some further googling on polyesther fabric and epoxy turned up some info from a boat builder forum that suggests that certain polyester fabrics with epoxy are used for abrasion resistance in wooden boats. The one issue they point out it holds about 1.5 -3 times the resin that equivalent weight fibre glass does so it will add weight to the board. However, lots of other benefits if it works - drapes across 3-d surfaces, abrasion resistant, printable with photo images. Definitely worth an experiment. Pricewise, it going to cost $50 setup fee and $80 per meter but the width is up to 1850mm so you can get 2 full sides per  meter or 5 on 2 meters of material so the price is in the territory of PBT etc.

Because plastic inherently has average to poor bonding with resins some of the PBT material comes with a 'fur' called remay on the back which hold extra resin and assists with bonding. However, its not see through so if you want to show off you wood core it won't be ideal and it also holds extra resin which means extra weight. I believe that the film without remay on it requires a good amount of heat to get a good bond. On this topic I was speaking to a sales rep at Dotmar plastics and he was telling me you can get one side laser etched and this helps dramatically with bonding the film.

Anyhow I can't get hold of the material cheaply so this is all academic.

The other approaches I've read about are to use stickers on the finished board and paint over with Clear Coat to protect them. However, this relies on the strength of the sticker adhesion which I suspect will not be good for long and especially if it takes a beating now and then.

The other, more viable option, is to print the designs on porous, translucent material and put it under the glass during the layup. Turns out its as easy as using an inkjet printer and printing on cotton, rice paper or, I suspect, any light weight paper. This would be ideal if your graphics are less than A4 size, for example, like a series of differ geometrical shapes or photos.

I recently spoke with a guy at our local beach who had just been over for a tour through the Decay Boards factory in NZ and bought a couple of great looking wood grain finished boards. He said that they printed on silk and then encapsulated them in the layup. Looked great.They graphics were translucent so you could see the core. Silk also is pretty strong in its own right so may contribute to the strength of the board.

I looked around our local area for printers who could print onto silk but again no luck. A google search turned up some inkjet printable silk sheets that have a backing paper on them that helps them run through the printer. I could only find a US source for these as well. However, it turns out that Quilters have been successfully creating their own paper backed fabrics (silk, cotton etc) to inkjet printing. They use 'Freezer Paper' which is paper used to wrap things to put in the freezer (clever name hey!) It is normal paper on one side and has a thin plastic coating on the other. If you lay your material on it and iron over the top of it the plastic melts a bit a sticks to the fabric. Apparently you can then run it through the inject printer and then just peel the freezer paper off.

This seems like a great option for decals A4 or smaller.

There are 2 drawbacks.Firstly, the PBT/ UHMWPE provides a scratch resistant surface whereas encapsulating the graphics doesn't add anything. If you're going to encapsulate graphics it might be a good idea to have s-glass as your last layer on the board as the extra strength improves impact and abrasion resistance. Secondly, your limited to images less than A4 size unless you have more luck in converting your injet printer into a continuous feed printer (I am sure there is a way to supress page breaks. Anyone, anyone???)

Googling around I came across an obvious and exciting option (obvious once it presented itself ,not obvious because it was obvious before). 'Glass on Surfboard decals' . These are digitally printed and are designed to be encapsulated in the fibreglass. Turns out there are a few suppliers not too far from where I live. Check this out:


These guys print on high tensile strength cotton so it will work great.

These guys, based in Burleigh Heads near where I grew up, print on silk and have have done some SUPs as well as boards.

I've emailed off to get a price and expect that it will probably come in around $60 per side based on the prices on their website for a full surfboard size decal  This is a big chunk of the price of the board but the results are amazing. If you google surfboard graphics it turns up loads of producers. Obviosuly it would be half the price per board if you did not cover the entire surfcae area of the board.....

(UPDATE - the decals printed on silk from StrykerMedia came in at about hald what I expected!!!!).

This is the image that I'm keen to get on the underside of the board. It joins it self as well so can be extended to the full length of the board although stretching it out looks good too.

The great wave off kanagawa by Hokusai