Resin Impregnator DIY

General Composites Discussions Equipment Talk
#1

Hi Everybody

Asking for prices of resin impregnators shows that such equipment is really out of reach for non professionals.
I wonder if there are any diy plans out there. I wasnt succesful in my search.
On the other hand we could share our thought on how such a device could be build.
http://www.prosetepoxy.com/process_equipment.html
This link shows the basic principle of such a machine.

However there isnt any squegee with adjustable pressure to squezze out excess epoxy and keep a constant resin fiber ratio. Adjusting the tension between both rolls against each other works well enough?
In one homebuild impregnator I saw that they were synchronized with two rubber wheels at each end.
What material would be easiest to clean? Epoxy adheres to stainless steel.
What bearings would be ideal? Teflon gaskets?
The resin bath recipient out of galvanized iron or maybe out of some flexible plastic that could be wrinkled to get of dry epoxy (nylon teflon?)

Well for sure there are alot of details i am overseeing.
Any suggestions?

#2

Was thinking that you can maybe get away with a wire-wound rod, (or lathed with gaps at specific depths cut into the rod), and some sort of bath…or by hand, for the resin. It’s like a film coating machine (see: Cheminstruments Inc EC-200) that lays down a metered amount of resin (due to the gaps in the rod) on the fabric. Don’t need any equipment because it’s just rolling on epoxy! any excess will flow forward. Table sized fabric pieces only of course.

As for your idea and equipment. I would suggest HDPE, UHMWPE, teflon, PP, etc plastics for resin areas. Should just wipe, scrape off with ease. Even the rolls can be teflon coated with a film. Resin bath can be any sort of plastic bag lined, or a plastic tub. We use HDPE bucket liners for our resin buckets for large batches. Can just wiggle the plastic, and pop out the extra unused resin block, and reuse the bucket.
There are many non-stick self-adhesive films you can get, like teflon, and other plastics. It would be a consumable of course. Check out C.S. Hyde for plastic films like that.

#3

Thanks for the valuable tips. Do you think using a wire-wound rod as the roller sumerged in the bath would distort uni fabrics under tension? Strange that manufacturers of these machines dont use teflon or similar. All the rolls seem to be polished stainless.

I believe the bath recipient would be out of some of the plastics layed into a thin galvanized sheet. So that i can allow the epoxy to dry and click it out afterwards. And fill the the galvanized bath afterwards with vinegar to clean the wire rod

My goal is to make a machine with which I can laminate a wing or fuse without qualified help. I need to impregnate 40 square yard for one wing half. The table roller would imply more work and somehow i feel the resin ratio would be more complex to control. However I will grumble over it.

#4

any reason you dont use a low temp prepreg and post cure in an oven after intial in mold cure?

#5

Well I dont exclude low temp prepreg but there are a couple of factors I dont like.
-Buying an industrial freezer

  • Build a 7 yard x 1,5yard oven (huge) The structure is iron an would deform at 120ºc
    -cost of prepreg
    -transport cost of prepreg
    -as the project advances slowly pressure to consume the prepreg in time
    What you consider thequality of a low temp prepreg part superior to impregnator machined part?
#6

There ARE several long outtime prepregs I think. Lewcott or Newport ring a bell, but it’s been awhile. As for the freezer, a simple chest freezer would work depending on your volume, but it sounds like you won’t be using much.

#7

well several complete carbon uni rolls maybe up to 6

#8

I think impregnators are really nice to slosh resin into fabric, but I never felt that you can minimise on resin that way. It still is hand laminating, and you need a slight extra on resin to “work” and bubble bust the fabric.

I have built a few impregnators (the last one 270cm wide, a huge machine) and the gap between the rollers was made visible using micrometers.

#9

What is maximum fiber content you can expect out of a manual impregnator? 55%?
With low temp prepreg 60%?
It would be great to see a pick of one of your machines. Maybe one medium sized of 120-140cm?

#10

are you impregnating UNI or Wooven?

#11

uni or multiaxial

#12

one off part or production?

#13

one off…initially two wing sets. But then are the molds for the stabilizers and a large fuse mold (this one by spring time).

#14

well if it was me I would go with the low temp prepreg, its more expensive but labor is much less and more importantly the product will be much better and more predictable. You would need to make an oven and post cure regardless, so that investment is there regardless of the process. You should get samples of prepreg and compare them to your own process. Regardless, make lots of test panels before making the wing.

#15

Would you have any suggestion for the kind of heat blower you would use for the oven?
Putting both mold wing halfes together would form a closed chamber as an oven.
A propane fueled blower would be ideal.

#16

sorry, I have no solution for oven design. What ever you do, it is important to have even heat everywheres, and controlable ramps and soaks.

#17

I was thinking about making a impregnator as well, however for my application I do not think that much precision is going to be needed. I am just getting started with a design and I will post what I think I am going to build for feedback as it evolves.

#18

Check the PDF. This is a smaller one. (I made pics of the large one, but no idea where these are)

#19

Very kind to post those pics.
They are enlightening on several details. A pitty they dont show details of the resin bath or do you simply pump resin between both rolls?
What resin/fiber ratio have you managed with such a machine?

#20

Resin goes between the rolls. Fiber/resin ratio is controlled by the gap size. Anything is possible. However, the springback of the fiber dictates Vf more than the impregnator. If you want good Vf, you will need vacuum or pressure.