Guys

I am after some advice please.

I've done a bit of wet layup and vacuum bag CF composite ( only simple stuff ! ) but am now looking to use infusion to create a flat panel ( approx 400mm x 900mm ) between two pieces of glass ( to be used as wing end plates on a hill climb car ). The construction would be :-

Gel coat-CF-Soric-CF-Gel coat

My question is, the two pieces of glass ( top and bottom mould ) will be larger than the composite stack so how do you stop the resin  taking the "easy route " around the composite stack and not wetting out the CF etc fully ? ( assuming the resin input is one end and the vacuum the other ).

Thanks in advance.

Adrian

This is just off the top of my head and who knows if it will work.

But what your trying to do looks pretty hard to me.

So for what ever its worth how does this sound.

1. you gelcoat must go right to the edge of the glass sheets

2. let all of your carbon and soric extend outside of the glass sheets.

3.Tape down the infusion end and the vacuum end with masking tape just to hold it firm.

4 Now with a bare sharp box cutter blade trip off flush with the glass edge all of the stack.

5 Now clean the edge of the glass and seal it with tacky tape the whole length of both sides.

6 You can now infuse and hopefully the resin cannot take the fast track up the sides because it is sealed.

I know this is way out there and if you go for it I would sure like to know if it worked.

Fred  

Hi Adrian,

It's a good question. What you need to do first is understand what it is that the resin wants to do. With the panel set up as you propose, what the resin will want to do is fill all of the low pressure 'voids' with the higher pressure resin. The means that what the resin wants to do is not make its way as quickly as possible to thr vacuum line but instead fill all of the lower pressure area between the sheets of glass meaning that it wouldn't be inclined to 'ignore' the laminate, even if it made it's way down the edges.

For the sake of slowing down the path around the outside of the laminate, I would suggest 'shimming' this area with some material of the right thickness (we use PTFE sheet for this exact purpose) but you could use anything you like that would make up the correct thickness. This will also reduce the chance fo the glass getting bowed. For obvious reasons it would be best to use something none-porous for this purpose.

Fred's suggestion of running the laminate all the way to the end also makes sense be we appreciate that this isn't always possible or cost-effective and so hence the shims.

In what's you're describing, gelcoat would be purely optional since the finish on both sheets should still be perfect without it. If it's for a race car we often don't bother with gelcoat.

I hope this helps and look forward to hearing how you get on.

Matt

Matt Statham
Easy Composites / Carbon Mods - Technical Sales

Matt, Fred

Thanks very much for the replies.

Matt,  i have made some wet layup/vacuum cf panels on glass with no gel coat which have been ok. My concern is the UV protection aspect, bearing in mind the end use of the panel/sheet (motorsport) is UV protecting not really  necessary ? or should the sheet be clear coated ? ( i don't currently have any kit to spray two pack clear coat )

Thanks again.

Adrian

Hi Adrian,

Honestly, for motorsport use we almost never worry about UV protection. Parts we've been making for years (5 years at least) that have been used on occasional use track cars still look absolutely fine. Generally, they'll get smashed or be replaced/changed before UV damage would be a problem and even if they did start to discolour just slightly it's not the end of the world. On a road car that sits in the sun all day then it's a different story and unprotected parts could start to look quite shabby after just a year or two without some UV protection but for track use, most people would rather save a few grams (and the hassle) of paint.

--Matt

Matt Statham
Easy Composites / Carbon Mods - Technical Sales

Matt

thanks for the reply, that make things allot clearer.

I will be ordering some consumables etc soon.

Thanks again

Adrian.

Hi Matt

Using the PTFE foam board as a brake on each side is really clever. I know that sooner or later I will use this method.

That is what I like about forums like this. The exchange of new ideas and technics.

Thanks

Fred 

I am planning on making some flat sheets by Vacuum infusion also. I assume in your case you are putting the fabric between two sheets of glass to have both sides shiney?? If I only need one side shiney can I just lay the fabric on glass, then the infusion mesh then bag right on top???

Thanks,

Hi Dennis,

Yes, that's dead-right. Making flat sheets by resin infusion onto a flat sheet of glass (make sure you use Easy-Lease chamical release agent; wax or PVA will be a total fail) is nice and straight forward and produces a really great sheet.

--Matt

Matt Statham
Easy Composites / Carbon Mods - Technical Sales

Just out of curiosity...When making a flat pannel do you draw the resin across the short side or the long side? Or os there a rule of thumb for all projects?

Thanks, Dennis