Super frustrated

General Composites Discussions Composites Talk
#1

Ever get stuck on a part, tweak something and try again, its no good, tweak something again, still no good and tweak until you don’t know what else there is to try?

I’m on the verge of just quitting because I’ve spent lots of time and money with nothing to show for a small, simple part.

Material preface
Epoxy resin : West System 105
Carbon fibre: 6oz
Spray adhesive: 3M Super 77
What I’m trying to make:

What I have made:

Open wet layup method 1
1)In-mold resin clear coat left to tack
2)Lay down carbon fiber layers on tacky resin, brush on resin and rolled between layers
3)Let dry 24hours then pull
Problems when I do this: Massive bridging. I let the initial layer of resin to tack before laying down my first layer of carbon fiber but it still doesn’t stick even after rolling it in.

Open wet layup method 2
1)Spray adhesive on first layer of carbon fiber, gently work it unto mold
2)Brush resin and roll between layers as usual
3)Let dry 24 hours then pull
4)Brush on a top coat of resin, sand, wet sand to 1500 grit, hand polish with Meguiar’s M105 and M205.
Problems when I do this: The spray adhesive hardens into many little matte white dots as shown in the pictures below. Also, when I sand and hand buff, it’s not very shiny and under direct light I can still see scratches (the part is too small and thing to use a DA polish) PS Ignore the dremmel cut but rather look at beneath the top coat

I’m trying to do this WITHOUT vacuum bagging. I really don’t have much motivation to fund any more extra tools and equipment without seeing any results first.

=(

#2

Keep at it!

Are you laying up on the back side of the parts you are trying to copy or on the side that is visible in the picture? Give us some more information and it will be easier to help you out.

I was at the point where you are now at one point and my whole attitude changed once I used a vacuum pump. It can be done on a relatively low budget. Consumables suck (especially on a college budget). I have found that painters plastic drop cloth works well as a bagging material (the thickest stuff Home Depot has, ~$2.00 USD for a ton of material)and duct tape works well as a sealant tape (~$3.00 USD). As for peel Ply ad Breather Cloth, youll have to order from a composites site but they both run on the order of <$5.00 USD/yard. Vacuums can get expensive, but APC Composites has a pretty good selection depending on what you have available to you in your work-area.

Working with composites can be frustrating at times, but you can get good results if you take some extra steps to ensure little stuff like this doesn’t hold you back.

#3

^^^ I second that.

I too will be stepping into vacuum bagging/infusions in the next few weeks. I’ve also been where you are at and have had the same problems. I did give up almost 10 years ago because of the same reasons as you. I must’ve wasted 2 yards of 5.7 oz 2x2 cf and hundreds of dollars on chemicals to make 0 parts. Now that I did my research and understand what needs to be done, I hope this time around I won’t waste so much money.

#4

Imagine I additionally spent $ on all those tools and much more time for laying infusion stack and I also sometimes get fail.

Hand layup is effective only on polyester parts w Csm , carbon dont act like csm and in my opinion hand laminating CF is just like shaping gold with wooden tools - at very start you are doomed.

#5

Imagine I additionally spent $ on all those tools and much more time for laying infusion stack and I also sometimes get fail.

Hand layup is effective only on polyester parts w Csm , carbon dont act like csm and in my opinion hand laminating CF is just like shaping gold with wooden tools - at very start you are doomed.

#6

These parts seem pretty decent to me. YOu can do some post work with resin and sanding and they’d be great. it’s a bit of work, but doable.

#7

I agree with everyone else. The first part with the bubbles can be fixed. Pop them or cut them out, and then layer in new epoxy. You can shape it with a hard plastic film or flash tape. Then sand and buff.

The second one: that is just learning the technique of spraying super 77 or any other spray adhesive. Don’t spray directly at the fabric or the mold, spray above it and let the droplets fall down to the fabric. Do this on a test piece and you will learn how to spray it light enough to not get those nasty brown glue droplets that ruin the finish.

My thoughts on the process overall is that it is a complex part with many sharp curves to have a wet lay be successful. Especially with a fiberglass layer behind it, which will not conform as nicely as the twill. I would use vacuum to get all of the shapes and contours. You can make a pump for cheap or buy a pump off of ebay (look for Gast or Thomas pump if you want a piston pump that you can use indoors). And bagging materials could be 2-4 mil plastic sheeting from lowes, and some batting from a fabric store as breather cloth–you still may want to invest in release film :P. If you do that (move to vacuum bagging), you could get better results. I think this part would be perfect for either vacuum bagging or with vacuum infusion.

Can we also see the mold that you have made to make these parts?

Regardless, this is a process of learning. As they “If it was easy everyone would be doing it.” We have all struggled, keep at it and you will achieve your goal.

#8

If you want cheap Vacuum bagging, just use the clothing storage bags. If your local hardware or homeware stores don’t have them, you can get them off ebay for 5 bucks. Then use your vacuum cleaner to suck the air out of it. Cheap and nasty and works like a charm for wet layed parts, no need for a vacuum pump. If you feel like it you can get peel ply and breather cloth, but they aren’t necessary either; the epoxy won’t stick to the bag and overlayed parts are going to be heavy so don’t be concerned about excess resin.

Also as said, you’ve used too much spray adhesive with your second part. It is possible to use it without affecting your finish, but you want to be spraying it so sparingly that you can’t even see it on the mould. Takes some practice.

You say you are using a mould, what is it? It looks like it is a male copy of your master, or is it just your master? That’s fine with wetlay, but it’s always easier to get a nice surface finish with a female mould. What release agent are you using? If you are using a semi-perm then you’re always going to struggle to get the layers to stick. Even with wax or PVA, you’ve treated the surface so that the epoxy won’t stick to it. You need to be very gentle when you’re laying up like that.

Keep at it, but in my opinion go with some form of vacuum bagging. Wet laying parts is process that I didn’t have the patience for.