Vacuum Press - Page 4

I'm out of my element here-- Silicone doesn't stick to much. This may be of some use to you:

http://www.compositescentral.com/archiv ... -4494.html

"I saw the video of them doing a hood bag.they used silicone tape around the edges.then some reinforcing fabric.then when you use the bag.you use tacky tape to stick the silicone tape on the bag to the tool."

"The trick when you want to use sealant tape, is to apply a double sided tape on the mould flange, and, sticky side up, flash tape (this is kind of fidly). Now when you brush on liquid silicone, it will adhere to the flashtape. The flash tape gives the silicone bag a place for the sealant tape to get hold off. Sealant tape will not adhere to silicone bags! (due to the vacuum you might or might not get a good seal)."

Hi there

I use the vacuum press system. I think it works just aswell as pneumatic pressing.

People always talk about not getting as much pressure which is true but to be honest thats irrelevant.

The good thing about Vac press is that it doesnt squeeze all the resin out of the ski/snowboard, It draws the air out of it which is exactly what you want.

I work for a well know car compostiies company and thats the exact way the car body parts are made, aswell as wind turbine blades and aircraft parts.

The amount of pressure doesnt play to much of a factor, aslong as its enough to push your materials into the shape of the mould.

I think that a pnumatic press is quicker though as a Vac takes a bit of setting up and then time to lay the release film,breather fabric and vac bag. Plus all these rings cant be reused....

Im running a vac pump i bought off ebay for £30!

Hope that helps

Check out my Facebook Page

Esc.Snowboard Co.

How relevant pressure is, depends on the core material and resin technology being used. Pressure is very relevant if you are not using prepreg. If you are using prepreg, it is dependent on the resin technology employed by the supplier.

I Know what you are saying. But most resins will react to temperature regardless of what pressure it is pressed at.

We use alot of different resins at work. all pressed with vacuum and heat.

Some of our stuff is prepreg which we use as it cuts down on mess and waste.

We used to make the resins for alot of the ski industry. SP 106 and 206. I think its now called west.

I used SP206 last year and was really good.

The core material will have an effect yeah. But for the thicknesses skis use then its not a problem.

I really recomend Vacuum pressing. When done well it can achieve amazing results. Check out RAMP, Deep Skis, theres a french builder swell whos skis look incredible but i cant remember then name....

Boheme skis.

There's nothing wrong with vaccum, but its important to point out that it is sub-optimal for a hand layup. The issue of resin ratio's can be fixed by setting up a small resin impregator. The issue of void content remains.

ok this might not be the best place to be asking this. That aside: some thoughts on this pump? http://www.veneersupplies.com/products/ ... 0-VAC.html

I know 3 cfm is a bit low, but for that price it is hard to pass up.

> backyardskier wrote:ok this might not be the best place to be asking this. That aside: some thoughts on this pump? http://www.veneersupplies.com/products/ ... 0-VAC.html

I know 3 cfm is a bit low, but for that price it is hard to pass up.

Wouldn't be worried about the speed - much faster than my old fridge motor - made 10 pairs of skis with that!

Too bad they don't show the Model number of this pump. A very common pump from Thomas is the 26xx models, mostly the 2660. Have a 2650 now and am completely satisfied!

I’ve been looking round at vacuum presses, and admittedly it’s getting a little hard to select one. When shopping for a bandsaw, jointer, or anything, there are masses of resources that evaluate models and brands available, now not to say the remarkable remarks from Knots. However, I’m having trouble figuring out what vacuum presses are top or now not. I’ve checked all the huge WW catalogs, some hyperlinks from this internet site, in addition to veneering books.

I realise that: thicker plastic is better, stronger vacuum pumps are better, bigger is better, but that is one of these things- I have a 14″ bandsaw due to the fact I couldn’t justify the 20″ version. I can’t just blow my coins on the largest and first-class without batting an eye.

Great thread! I’m still in the planning stages and go back a forth about vacuum pressing. Been looking at the Joe Woodworker V4 Plus Project (Venturi). https://www.veneersupplies.com/products ... s-Kit.html

However I live at 5700’ elivation which means I’m gonna loose 2.5psi est. right off the top. Would this be too much loss in psi for a good press? Has anybody used a Venturi pump for a vacuum press?

I did build my first boards with the vac-pro venturi + a 25l tank from an old compressor for vacuum "storage", works great. You just need a compressor big enough

The shapes were done in Draftsight which is a 2d cad program that is still free as far as I know. Figure out your design specs and start drawing. If you need specifics I can try to send you some of the drawing files but you’ll still need to download draftsight to open them. The 3/4 mdf was cut on a CNC and bolted together - the holes are 5 cm apart for adjustability. Well worth finding a good CNC shop to cut the designs unless you’re just into suffering. I’d rather spend time building than making mould parts. Obviously tip/tail moulds can be changed.

Thanks for the response, I will check out the draftsight application and see if i can come up with a camber profile. I assume that it is user friendly? I do not have a lot of experience with CAD software.

This might be a big ask but any chance you have a photo of the mould with out the topsheet? I am having trouble wrapping my head around how you get the length adjustable or how your top sheet is bridging the gaps in the MDF.

Also, where are you plumbing the vacuum hose into the table? Is it under the mould with channels leading out? Or are the channels underneath the tops sheet and exit at the tip and tail of the mould.

The base of the table is two layers - the bottom layer is 3/4 mdf and the top layer is 3/4 melamine screwed together at the corners. MDF by itself is too porous and the vacuum won’t work as well. I copied OACs design years ago and haven’t changed much. The vacuum line is one hole in the center of the table. Can’t remember the exact details but a brass nipple fit tightly through the mdf with a counter sunk hole in the melamine with a brass nut and lots of clear silicone. This has always been the weak point in my setup that is easily solved with lots of silicone at all the points where the line comes through the table.

I’ll see what I can find for pictures of the moulds. Design the tips and tails for the length and rise that you want then add a long flat section that extends into your camber mould and add holes every 5 cm for adjustability. The holes attach to your various camber moulds. The camber moulds are designed for the running length of the ski and whatever camber you have in mind. I have 1050mm,1150mm,1250mm and 1350mm camber moulds with 4 to 6 mm of camber. For the camber moulds add the holes every 5cm in from the end of the contact points towards the center of the mould. This allows for a pretty wide variety of ski lengths for the kids and wife. If this doesn’t make sense let me know.

I use a metal sheet - aluminum over the mdf mould for layup. The pictures of my press have the aluminum sheet over the mould.