I making small CF interior parts for a local race shop in town, my first part was a wet layup vacuum bagged piece. Im finding better time tables with the infusion process. What do you guys use to get the first layer of CF to stick to all the contours in the mold. I have been playing with 3m 77, it works great but prevents a good infusion on the surface of the part, and it leaves residue in the resin on the surface. Remember im new to this stuff so please be very descriptive with your suggestions, Thanks alot.
It does not if you infuse correctly are you sure you carbon is saturated.? I thought the same a while ago when i first used it, slight adjustments to my layup and iv been pin hole free and perfect surface on id say 20 infusions with 3m77 spray
Show us a pic of your layup
how much spray do you use?
well i try to use very light coats of 3m, the first time I also used PVA. The second time is used the 3m i did not use the pva. I am using a polyester based resin, is there something that is better for infusion. The polyester resin is a little thick, any suggestions.
Try to infuse with infusion epoxy. Polyester may cause problems when using in infusion. The pinholes can be caused by gas from the resin.
And always use a minimum of spray adhesive.
what do you mean a pic of my layup?
We use Airtac from Airtech. It’s not cheap but used in a light dusting manner it will hold fibre in place quite well. It is certified for use in aircraft parts so when used correctly it won’t affect the resin.
I used to use 3M and got the tacky residue on the resin surface as well.
I switched to a epoxy specific spray adhesive and I dont have that problem anymore.
The spray I use is called Epoxz and is by Westech Aerosol. It binds to the epoxy so it doesnt leave that tacky residue that standard spray adhesive did. I bought I case of 12 cans and it cost about $10 a can so it is similar in price to the 3M 77
Thats a perfect one, I have tested it. The Airtac 2 from Airtech is also very good. For normal parts i use a cheap one that works perfect. Test some cheap spray adhesives, there will be one that works.
Guys I really appreciate all the feedback, do any of above listed sprays leave residue in the resin surface coat. also I was wondering if anybody uses a pre resin coating and wait for it to tack up than lay the carbon in the mold. what resins do u suggest for infusion?
Take a look at that video, I think it will answer some questions. I never had Problems that the adhesive is visible.
http://www.compositescentral.com/showthread.php?t=6530
can anyone tell me where i can get some 3M 77 or similar from in the UK? i’d like to try it out for myself.
you can buy 3m 77 from east coast fibreglass, talk to Gary, Very helpful people and excellent discounts are offered if you are buying in larger quantities.
Is this it under a different name?
http://www.ecfibreglasssupplies.co.uk/p-2214-aerofix-2-spray-adhesive-500ml.aspx
yes that is one and the same.
/as for using epoxy or polyester:
If price of the product and speed of cure is important, you can do the following:
-apply a (spray) gelcoat (transparent). Preferably UV stable (MMA modified) and for exterior use (ISO-NPG).
For instance Nord Composites GC 161 colour 9903
Let this cure to a tacky state. Now install your fibers. I prefer not to use 3M 77 as I have seen too much problems with it. Airtech Airtac2 is OK, as is Ce-Sense Resin Infusion Spray Glue (www.cesense.nl)
Now infuse with an infusion polyester. These are non-modified (not thixotropic) and infuse well. They usually are thinner than epoxy resins.
I suspect you have been infusing with hand laminating resin. Although this might work with epoxy resins, the rheology of polyester is such that you will run into trouble if infusing something larger than a very small item.