Vacuum molding

[simso]

Oh, another thing. I've found short nap 3" foam rollers work best for applying epoxy to the veneers. i use Wooster R039 trim rollers or WEST brand foam roller cover cut in half. This applies a thin, but uniform layer of glue. I wet out both faces of an interface to insure against dry spots. I have used other means like disposable brushes and toothed squeegees but rollers are much better for even distribution in a thin layer and faster too. If you are not using epoxy, however, my foam rollers comments may not apply.

Thanks craig, your info has been very welcome and appreciated, it has certainly reduced my experimenting phase.

Is this the standard epoxy you are refrring too

https://www.carbatec.com.au/joinery-and ... ack-c-4ltr

Steve

[Craig Bumgarner]

Yes, that's it, WEST 105 Resin. I use the 205 fast hardener for laminating. Though "fast", there is still plenty of working time, especially once it is rolled out. I've never lost a batch due to kicking before I could get it applied. Once rolled out, you have at least 30-40 minutes working time if need be. Usually only takes me 5-10 minutes to get the plate into the vacuum bag and the vacuum drawn. Cures enough to remove from the vacuum in about 4 hours. The epoxy is still a bit flexible and not fully strong so if I have a spot that sticks to the mold it is easier to free up at this stage (wax your mold well or use plastic sheet between the mold and veneer, wax works for me). I usually pop the plate back in the vacuum for another 4 hours to get it fully set, helps overcome any tendency of the wood to have its way with the shape.

I use WEST 105 resin and 207 clear hardener for grain filling before finishing as it makes less amine blush. Before I switched to this I used System Three which worked, but much slower cure. West 105/207 can be sanded without corning in 24 hours which is still to long for me, but better.

One key to using epoxy is accurate measuring of the mix ratio. I used to use the WEST metering pumps, but there is a lot of waste this way. Now I use cheap digital gram scales ($14US on Amazon) that measure to 0.01 gram and can mix very small batches if need be, as little as a couple grams if need be. I keep the 105 resin in an 8 oz. squeeze bottle and the hardeners in a 2 oz squeeze bottles. These are perfect for mixing small batches.

[curly]

G'day all , it's been a while . I'm puddling around with the idea of actually building an instrument again , rather than handing all the fun over to everyone else. Laminate is definitely part of my preferred build style .
Just wondering if anyone has found a good ready made bag that I can order domestically ? The rest of the get up I can just temporarily pinch of my timber stabilising get up I reckon .
Thanks
Pete
Curly timbers

[blackalex1952]

Just wondering if anyone has found a go ... stically ?

I am also wondering where to get bagging tube. Vacuum bagging film needs to be edge sealed if one wants a bag. To make sides, the laminates are placed in a bagging film tube, then a vacuum formed, then the sides are clamped onto a mold in the shape of the sides.
Backs can be laminated using a flat sheet surface, eg recycled thick glass and a sheet of bagging film sealed at the edges onto the glass with the yellow seal tape which resembles blu tack in texture.
Aldi had a special on a vacuum bag for use with a vacuum cleaner and intended to store linen. I modded the connector on the ones I bought and have successfully used them for bagging, but they are a thick plastic and wont stretch the way bagging film will for compound shapes. Cheap as chips so good to try out and held full vacuum pressure from my Gast vacuum pump set up.
Bagging film is basically of two types. Nylon and PVC or PVC/Nylon blend. Nylon bagging film has to be ultrasonically welded but the PVC I have used can be heat welded, even though it has a little nylon in it.
The nylon film is more costly and has high temperature properties, so is not so essential for luthierie. I am about to purchase an el cheapo Chinese made 400mm heat sealer from eBay. $24 odd $$'s free delivery from a supplier in NSW. Not so good for the long edge of a bag made out of sheet, but from PVC tube it will most likely be fine for making a bag for doing sides. Here is a US supplier who sells the tube by the metre. I haven't found any supplier in Aus who sells tube in anything than huge rolls, expensive due to the quantity. The tube from this supplier is nylon, but can be sealed at one end with the yellow sealing tape and packaging tape, or someone with an ultrasonic sealer could do it. Haven't found any one in Aus except for an industrial distributor who can have them made by their supplier in the US for major$$'s.
special order. The other end is sealed in my case with a dowel and a clip made from electricians conduit. I run a piece through my band saw to take a little off to form a clip then round the edges so that it snaps on to the dowel. Leave the dowel longer than the clip otherwise it's hard to disassemble.
You will need release film and breather fabric inside the bag. I have used plastic film and shadecloth for a cheap successful project. If you have problems with the release film you can use the proper stuff which has holes in it along with , but if the resin quantity is applied as a minimum ala Craig Bumgarners post there is hardly any resin squeeze out into the release film. Cheers Ross