Was just thinking about with other applications and people talking about getting a finished surface straight out of the bag when using peal ply… (and other bagging meda I’m not familar enough with).
Does this mean that with the needed skill of getting everything into your bag that there is no need to hotcoat a board afterwards when bagging the outer glass?
Bert, do you hot coat?
Not hot coating would save a lot of weight (or maybe I’m just not sanding enough back off after my hot coat).
OH and who is bagging their outer glass? (with all the great bagging work I’m loosing track of who is doing what and with which techniques:)
I always bag on my glass (in one form or another). Although I always hotcoat I started to question if it was necessary on my last board. I think that if its possible to skip the hotcoat you would need to bag at higher pressures and get your resin distribution perfect.
I think you definitely still need to hotcoat. The bagging gets the glass nice & flat & takes excess resin out of the weave, but you still have to sand/surform the laps, folds, etc. You might get a smoother finish without the peel ply & absorbent - then the excess resin would be pushed into the balsa and not sucked out through the peel ply. You wouldn’t save weight, though.
then the excess resin would be pushed into the balsa and not sucked out through the peel ply. You wouldn’t save weight, though.
But if you were measuring 1:1 then there shouldn’t be extra resin (I think you would have to have a lot of trust in your ability to go without the hotcoat (which I don’t have)). When my laps came out of the bag I could hardly see them. I think that all they would need is a lite epoxy basting and sand to be good to go.
I always (to date), bag my lams, and have always hotcoated. I do not use peel ply, but a release film and some bleed/breather of some sort or another, the lams come out shiney and pretty flat, there are some ridges, but only resin.
You can see the cloth weave, so based on wanting to sand and not wanting to sand through a 2oz skin, I always hotcoat with approx 100g of resin per side, most of which is sanded off.
4est: here’s the “Bert said” I came accross today (hopefully I’m not misconstruing this):
Bert on September 29, 2004–
a good bag can give you a finish …
ive pulled boards out the bag that look like theyve just been buffed
[on peel ply] all the other products you mentioned are a hoax and a waste of money …
just 2" tape and a bag is all you need …o ’ and some bubble wrap …
I have no experience with this, just came across it while lurking and thought it was relevant to you discussion… It’s from the Vacuum Bagging a composite balsa skin thread
marky would agree , that even tho you can get a great finish straight out the bag , it has room for improvement …
you can have a surface that looks like its just been buffed , but if you look close youll see the tiny bubbles in the weave , they still need to be dealt with for total clarity …
you could leave them there or sand the surface and finish coat , depends on how particular you are …
and yes a good bag makes the difference , especially one with a little stretch …