Peel Ply mis-use or something else?

SilicdyneTRF
Shop deals on ebay
The Rocketry Forum

Help Support The Rocketry Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
REK

REK

Well-Known Member
TRF Sponsor
Joined
Feb 21, 2012
Messages
3,090
Reaction score
109
Location
El Paso, Texas
I made a 50" wide 98mm fiberglass tube the other night using the left over infusion resin I had and then added a touch of my favorite peel ply along with some perforated shrink tape feeling the need to keep the epoxy in place. I woke up this morning to find that it had all these massive dry spots. I have yet to remove the tape and the peel ply. Can someone explain why this sometimes happens please. I'd like to avoid it.

ImageUploadedByRocketry Forum1410453262.418841.jpg


Alexander Solis

Level 1 - Mariah 54 - CTI-I100 Red Lightning Longburn - 6,345 Feet
 
It happens when bubbles in the fabric stay in the fabric.

This is alleviated by technique (massaging them out with fingertips) and by switching fabric. Some weaves (especially tight ones) become completely airtight when wet out, making it impossible to get bubbles out without vacuum bagging (which itself is a challenge on tubes).
 
CarVac said:
It happens when bubbles in the fabric stay in the fabric.

This is alleviated by technique (massaging them out with fingertips) and by switching fabric. Some weaves (especially tight ones) become completely airtight when wet out, making it impossible to get bubbles out without vacuum bagging (which itself is a challenge on tubes).
Click to expand...

I guess this will be the last time I use 8HS on such a large scale.


Alexander Solis

Level 1 - Mariah 54 - CTI-I100 Red Lightning Longburn - 6,345 Feet
 
Could the humidity also be the cause of this?


Alexander Solis

Level 1 - Mariah 54 - CTI-I100 Red Lightning Longburn - 6,345 Feet
 
I have had that happen when temperatures have been elevated during initial cure, where rapid outgassing will cause a rise in the fabric.

I think when the initial cure temps have been at 95 F and below it's been greatly reduced.

Greg
 
GregGleason said:
I have had that happen when temperatures have been elevated during initial cure, where rapid outgassing will cause a rise in the fabric.

I think when the initial cure temps have been at 95 F and below it's been greatly reduced.

Greg
Click to expand...

I was going to put blame on me heating the shrink tape, however long before I did it I woke up around 4am to see the peel ply had lots of lumps and dry spots on it, much like the one you see in the picture. When I saw that I had removed the messed up peel ply and added a new one with more care not to get any bumps. I added the tape shortly after that.

Could it be possible also that the peel ply is sucking up too much epoxy? I'm pretty confident I oversaturated this peel ply.


Alexander Solis

Level 1 - Mariah 54 - CTI-I100 Red Lightning Longburn - 6,345 Feet
 
SinfulDarkLord said:
I guess this will be the last time I use 8HS on such a large scale.


Alexander Solis

Level 1 - Mariah 54 - CTI-I100 Red Lightning Longburn - 6,345 Feet
Click to expand...

Satins are bad with this because they have lots of parallel fibers on each side which effectively block air from going through. I like a nice open plain weave when using fiberglass.
 
Hmmmm ....

I initially thought those were bubbled areas after my rather cursory look. But taking a closer look they look like they are resin starved.

I've never worked with infusion resin. Is the viscosity more like water? My experience has been with Aeropoxy laminating products.

Could it be that the airframe soaked up too much, leaving the fabric resin starved? It will migrate to wherever it is getting the most "suck".

Greg
 
GregGleason said:
Hmmmm ....

I initially thought those were bubbled areas after my rather cursory look. But taking a closer look they look like they are resin starved.

I've never worked with infusion resin. Is the viscosity more like water? My experience has been with Aeropoxy laminating products.

Could it be that the airframe soaked up too much, leaving the fabric resin starved? It will migrate to wherever it is getting the most "suck".

Greg
Click to expand...

I really see not much difference other than it flows more. Not close to water thin more like pancake syrup. I sometimes believe that it is, because of that thickness that it has a hard time penetrating heavier fabrics. I spent two hours laminating this tube.

It could be possible that it needed more resin. I even managed to use at least from what I mixed a total of 366 grams, plus a few extra for the peel ply. According to my previous attempt I used at least 488 grams plus the few for the peel ply.

The other factor is I used 5 layers and was able to wet it out with those 366 grams of epoxy. My previous attempt was 4 layers with 488 grams.

The tube is still good other than probably will just have surface imperfections where the epoxy was starved.

I'll have to wait until tomorrow to remove the tape and peel ply. This epoxy takes a really LONG (at least two days) time to harden.


Alexander Solis

Level 1 - Mariah 54 - CTI-I100 Red Lightning Longburn - 6,345 Feet
 
SinfulDarkLord said:
I really see not much difference other than it flows more. Not close to water thin more like pancake syrup. I sometimes believe that it is, because of that thickness that it has a hard time penetrating heavier fabrics. I spent two hours laminating this tube.

It could be possible that it needed more resin. I even managed to use at least from what I mixed a total of 366 grams, plus a few extra for the peel ply. According to my previous attempt I used at least 488 grams plus the few for the peel ply.

The other factor is I used 5 layers and was able to wet it out with those 366 grams of epoxy. My previous attempt was 4 layers with 488 grams.

The tube is still good other than probably will just have surface imperfections where the epoxy was starved.

I'll have to wait until tomorrow to remove the tape and peel ply. This epoxy takes a really LONG (at least two days) time to harden.


Alexander Solis

Level 1 - Mariah 54 - CTI-I100 Red Lightning Longburn - 6,345 Feet
Click to expand...

What was the mass of the fabric?

Also, you took way too long to finish laminating. Depending on the working time, of course. For PH3660 hardener, I would try to get it done within half an hour at the most of mixing the epoxy, because it becomes hard to work as it gels.

Because you took so long, by the time you squeezed it down, the epoxy was at the point where it was reluctant to go anywhere.
 
Last edited:
CarVac said:
Satins are bad with this because they have lots of parallel fibers on each side which effectively block air from going through. I like a nice open plain weave when using fiberglass.
Click to expand...

Me and my tight weaves I swear. I even ordered that tightly woven plain weave fabric from ACP Composites. Only difference however, is that it is lighter being 6oz. instead of 9oz.

Do you think that fabric will also present a problem with dry spots?


Alexander Solis

Level 1 - Mariah 54 - CTI-I100 Red Lightning Longburn - 6,345 Feet
 
CarVac said:
What was the mass of the fabric?

Also, you took way too long to finish laminating. Depending on the working time, of course. For PH3660 hardener, I would try to get it done within half an hour at the most of mixing the epoxy, because it becomes hard to work as it gels.

Because you took so long, by the time you squeezed it down, the epoxy was at the point where it was reluctant to go anywhere.
Click to expand...

I was using infusion resin with the 3 hour long pot life.


Alexander Solis

Level 1 - Mariah 54 - CTI-I100 Red Lightning Longburn - 6,345 Feet
 
I forgot to mention I mix in batches separately not all together. By that I mean I mix a set of 100 grams to 22 grams. This way my mix ratio is accurate and also gives me more time.


Alexander Solis

Level 1 - Mariah 54 - CTI-I100 Red Lightning Longburn - 6,345 Feet
 
Last edited:
Okay so here is my assumption on what happened. The resin was too thin that it flowed to other areas and left the peel ply dried areas. Perhaps using a more thicker version such as the PR2032 would be a much better solution.

What do you guys think, sounds reasonable enough?


Alexander Solis

Level 1 - Mariah 54 - CTI-I100 Red Lightning Longburn - 6,345 Feet
 
Just last night I glassed an airframe with PR3022. It was ~26 gram batch (the cloth weighed about 26 grams) on a 17" x 15.5" section of ~6 oz on an 2.60" OD x 15" long airframe. I added a bit of milled fiber and spent over 3 minutes stirring with a craft stick chucked into a drill press (just to make sure it was thoroughly mixed). Outside temp was > 95 F. After about an hour or so it was starting to kick. No peel ply and used a aluminum roller. I held it to the light and let the glare picked up the over-saturated spots, then rolled off the excess. I had a bit of epoxy left over, so I got thorough saturation without too much excess.

So, it works for me.

Greg
 
GregGleason said:
Just last night I glassed an airframe with PR3022. It was ~26 gram batch (the cloth weighed about 26 grams) on a 17" x 15.5" section of ~6 oz on an 2.60" OD x 15" long airframe. I added a bit of milled fiber and spent over 3 minutes stirring with a craft stick chucked into a drill press (just to make sure it was thoroughly mixed). Outside temp was > 95 F. After about an hour or so it was starting to kick. No peel ply and used a aluminum roller. I held it to the light and let the glare picked up the over-saturated spots, then rolled off the excess. I had a bit of epoxy left over, so I got thorough saturation without too much excess.

So, it works for me.

Greg
Click to expand...

I've always wondered if it was nessecary to put peel ply on fiberglass. Unlike Kevlar it is very sandable without having it fuzz or does it? I have yet to sand that deep into fiberglass.


Alexander Solis

Level 1 - Mariah 54 - CTI-I100 Red Lightning Longburn - 6,345 Feet
 
SinfulDarkLord said:
I've always wondered if it was nessecary to put peel ply on fiberglass. Unlike Kevlar it is very sandable without having it fuzz or does it? I have yet to sand that deep into fiberglass.
Click to expand...

This question makes me think there's something you're not understanding about peel-ply. How would it affect sand-ability? I've done quite a few non-rocketry related projects using Kevlar and never used peel-ply unless I was vacuum bagging. In fact, I can't think of any use for peel ply outside of vacuum bagging or other types of compression molding.
 
In my experience peel ply improves sanding especially with 6oz or higher weaves of FG. I normally use plain weave. It also depends on the FG manufacturer. I like ACP composites cloth I get the best finish with less sanding. I also think peel ply holds the fabric down better. The large dry spots may have been a lack of resin in the weave. When I work the peel ply with FG if I notice there are are dry spots in the peel ply I pull back the peel ply and add more resin to the weave. I work in the resin and then reapply the peel ply. If I can get my peel ply really wet using a foam roller or brush I normally do not have dry spots in the FG.
 
When using long cure resin this will happen. The resin will drain to the lowest area. In some cases if you get to much resin you can float the laminate.
 
watheyak said:
Hmm. I think I'm having a semantics issue with peel ply and release film.
Click to expand...

Peel ply is woven fabric, often polyester ("Dacron") which leaves a rough bonding surface. It is very permeable to epoxy.

Release film is film: smooth plastic sheet material occasionally with holes for some degree of permeability, and which leaves a smooth surface not so well suited for bonding afterward. There is really no reason to use both, ever, unless you are using breather cloth and that is sticking too tenaciously to the peel ply.
 
CarVac said:
Peel ply is woven fabric, often polyester ("Dacron") which leaves a rough bonding surface. It is very permeable to epoxy.

Release film is film: smooth plastic sheet material occasionally with holes for some degree of permeability, and which leaves a smooth surface not so well suited for bonding afterward. There is really no reason to use both, ever, unless you are using breather cloth and that is sticking too tenaciously to the peel ply.
Click to expand...

Yep. So which was used in this thread? And I definitely agree that the only reason to use either is to keep the layup from sticking to the breather.
 
Last edited:
watheyak said:
Yep. So which was used in this thread? And I definitely agree that the only reason to use either is to keep the layup from sticking to the breather.
Click to expand...

Peel ply was used beneath shrink tape (which resembles release film but has its own utility).

And no, I meant that you can use either at any given time, but never both together. (I have seen this, and it is usually either a waste or a disaster)
 
Getmore said:
When using long cure resin this will happen. The resin will drain to the lowest area. In some cases if you get to much resin you can float the laminate.
Click to expand...

That makes sense. Maybe I need to try a shorter cure resin for the peel ply.


Alexander Solis

Level 1 - Mariah 54 - CTI-I100 Red Lightning Longburn - 6,345 Feet
 
Tube is pretty good except for the unfortunate dry spots. In this case I guess it doesnt matter since glass is usually painted. Some good sanding and its ready to be used.

Tube:
ImageUploadedByRocketry Forum1410551469.196701.jpg

Dry spots:
ImageUploadedByRocketry Forum1410551488.693185.jpgImageUploadedByRocketry Forum1410551496.932054.jpg


Alexander Solis

Level 1 - Mariah 54 - CTI-I100 Red Lightning Longburn - 6,345 Feet
 

Similar threads

Cl(VII)
Sold Composites and Vacuum Bagging Supplies
Replies
3
Views
907
Cl(VII)
Cl(VII)
REK
Peel Ply Tech-Tip
Replies
10
Views
3K
REK
REK
REK
AARD Dimensions?
Replies
5
Views
2K
NateLowrie
NateLowrie
REK
98mm Fiberglass Tube
Replies
4
Views
892
REK
REK
REK
Carbon Stuff
Replies
1
Views
802
REK
REK

Latest posts

Back
Top