CSM sheds and is clumping up during layup

[chieftaing]

I'm new to boat/fiberglass repairing but thanks to the many awesome posts on this forum and elsewhere things have been going well. I'll be posting some project/pictures soon, but hit a situation when doing my first layer of 1.5 oz CSM on the underside of replacement deck and needs some guidance.

I tore a slightly oversized piece of 1.5 oz CSM to fit the replacment deck piece, spread the poly resin + hardner on the (marine) plywood deck and let it set up a little, layed down the CSM, and then went to wet it out (I think thats the term I should use - don't want to sound too confident!). The chip brush I was using started dragging clumps of the mat - not good. Tried the 3/8" fiberglass roller that I had been using with great success on the 1708 I used days before to tab some bulkheads and some stringer repair - but that was worse - dragged fibres everywhere. Ended up using a 6" plastic trowel (from auto store for use with bondo) and dragged the resin around. This was best but still pulled fibres out of the mat into clumps.

So - how do you properly wet out the CSM without pulling it apart?

The two pieces I did came out OK, but not great. Some definite white spots where I guess I didn't saturate it enough. It did cure and the properly done sections look great.

Thanks everyone.

 

[sphelps]

After you wet the plywood and let it soak in for a while before you lay your csm down . Roll some more resin on the ply then lay your csm down into the wet resin .. Add more resin on top of the csm then roll from the center out working the mat clear and removing bubbles that may form ..

 

[tpenfield]

For a medium size piece, and depending on the type of surface I want, I will soak the base wood really well and apply the CSM, then lay a piece of plastic over the area (like plastic drop cloth) and roll the plastic rather than make direct contact with the resin.

Keep in mind, there is not much holding the CSM together, so the resin application has to be without much disturbance.

If I am doing a small piece, same thing, lots of resin underneath the CSM and I will just dab with a chip brush rather than brush strokes. one of the mistakes that folks make is putting the cloth on a fairly dry surface and then trying to apply the resin over it. . . Does not work as well as as applying dry cloth to a well wetted surface.

For cloths like 1708, I will just apply the resin to the back side of the cloth, which is easy since it is stitched cloth, let the resin soak in a bit and then slap the wetted cloth onto the work area. Very quick, rather than trying to get resin to absorb into the cloth.

 

[MTboatguy]

What temp and humidity was it when you were trying to do this?

 

[chieftaing]

High 70's maybe low 80's with probably 80% humidity. Last night outside Boston. Using US Composite's poly resin with their hardener; mixed up about a quart at a time and mixed it for a solid 2 minutes with a spoon - I'll switch to a drill mixer tonight. The resin was nice and hard this morning so I think the "mix" is OK.

I think Admiral tpenfield is right about not having enough resin built up on the deck first before laying down the CSM. I tried to apply the majority of the resin from the top onto the CSM after I had layed it down, and then spread the resin around - disturbing the mat too much. I have another piece to do tonight - I'll see how it goes.

Thanks.

 

[gm280]

I say follow sphelps suggestions in comment #2 and your problems will be fixed. I had different experiences myself with my boat project and after following the procedures sphelphs suggested, it works great. I also use a 4" wool-like roller and not the foam rollers. You can move around a lot of poly with the roller setup and get the CSM saturated easily and work out a ton of bubbles if need be... :thumb:

 

[MTboatguy]

I have never had any success using a foam roller on glass, I use a heavy metal segmented roller when I am doing glass work. But as Wood Says, I am old!

 

[sphelps]

I love these ..
http://www.harborfreight.com/pack-of-six-4-inch-mini-paint-roller-covers-97810.html
Once they are good and saturated with resin they work great .. Did all my stringers and transom and never had to use a chips brush ..

 

[Woodonglass]

Yup, the rollers Sam posted ^^^ are the best for rolling resin. Chip Brushes are Great for corners and DABBING edges. You NEVER want to use brush strokes with a brush on CSM. It will never turn out well. On flat work you always want to be rolling resin and never on dry CSM unless you're using a bubble buster roller. You only want to use enuf resin to make the mat or fabric go clear and then stop. To much resin is a bad thing. Keep workin at it You'll be a pro in no time!!!!

 

[JASinIL2006]

i never really liked working with CSM for reasons listed above. Compared to 1708, CSM is just too fragile. i got better the more I worked with it, but it was always a bit of a struggle. I'd rather spend more on biaxial and save myself the aggravation.

 

[tpenfield]

High 70's maybe low 80's with probably 80% humidity. Last night outside Boston.

Boston area ? . . . I sent you a PM.

 

[Quantumn]

Hello there Chieftaing, allot of great suggestions and hints from the Iboats experts. I myself was having the very same issues as you early on in my restoration. First thing I wanted to ensure before I tackled large sheets of csm was to experiment/practice on smaller pieces with csm. It was not pretty at first, but utilizing the suggestions of everyone here, I was able to become a self proclaimed journeyman in my own little feeble mind. I have utilized everyone of the tricks mentioned in this thread with great success.
A couple other hints I have learned is to warm up the resin your about to use prior to mixing in a cake pan/bucket with hot water. This helps the viscosity of the resin and allows it to flow much better (though my ambient temps are about 20 degrees lower than yours). Also ensure the piece your working on is clean so a quick sanding with 80 grit, a good vacuuming and thorough wipe down with acetone prior is a must.
And last, what I have used to help me remind myself, I mounted a simple white erase board with steps/procedures near my work space. It may seem silly, but the first time you forget to add catalyst or mix the wrong amounts, you will think twice about that simple $5 dollar helper.
Just a few things to help out, though I can not take credit for these practices, I bow to the helpfulness of this community for my newly learned skills. :grouphug:
(hint, we like pictures, hint)

 

[gm280]

I love these ..
http://www.harborfreight.com/pack-of-six-4-inch-mini-paint-roller-covers-97810.html
Once they are good and saturated with resin they work great .. Did all my stringers and transom and never had to use a chips brush ..

Those are the same type rollers I use as well. Except I buy mine at Lowes for more money because the HF near me is about 45 minutes or more away. So a little more cost at Lowes I guess is worth the trade off in gas. I did use the 4" foam rollers. And I have to say , if you are doing a small to medium size area, those foam rollers work pretty well. Problem with the foam rollers is they start to come apart after a while. So I switched (as I was told I would by WOG) to the wool-like rollers and they hold up really well for any size effort. And I don't try to clean them out after using them, but simply throw them away. Again the trade off of buying Lacquer Thinner or Acetone to wash them out cost more then replacing the roller in my experience... Post those pictures...we all love pictures... :thumb:

 

[Woodonglass]

You can get those rollers at the Dollar Store, Dollar General, Dollar Tree, Big Lots, etc... CHEAP!!! Use em and Toss Em!!! Not worth tryin to save em. I even get Paint brushes at the Dollar Tree sometimes 4 for a Dollar. and Mixing Containers too!!! Being a C.O.B. I'm always looking for CHEAP stuff.I may be Dumb but that don't mean I'm Smart!!!!

 

[Mark72233]

chieftain, its already been said but I will say it again. Use chip brush to dab corners and tight spots rollers cant go. You referred to a 3/8 fiberglass roller, if you mean a bubble buster I hate using them and they never worked for me on CSM, just grabs the fibers and rolls them up and makes a mess. It works ok on 1708. I tried the foam rollers and the standard paint rollers and I like the standard paint rollers, probably because that is what I started with and used most. I buy the big pack of 9" rollers and cut them down to 3" or 4" pieces with a cut saw.

 

[chieftaing]

Thanks everyone!

Glassing the underside of the 3rd (and last!) piece of replacement deck went much better last night thanks to all your help/suggestions.

I wetted the 1/2 marine plywood really well; there was a definite "layer" of wet resin on top into which I layed the CSM.

I did pour more resin on top and then used the 4" foam roller to get everything really wet, nice edges, etc. Didn't use the "bubble roller" (3/8 long wheel with many pizza-cutter looking rows) at all.

I screwed up the ratio - only used enough hardner for 1 pint but used 3 pints of resin - however it was fully cured and rock hard this morning. Thank goodness for US Composite's good stuff and I guess dumb luck. I'll be buying that cheap whiteboard to jog my memory like was suggested!

I ended up using a full quart of resin/hardner for a piece that was 17" wide by about 48" long. Probably too much - but probably what all you experienced folks would expect for a newbie like me . Now that I've regained some confidence in CSM, I'll work towards getting better about resin amount. Let's see - that's 5.6 sq feet, so that's 8.5 oz of glass; the FAQ says 3-4 oz per sq foot of 1.5 oz CSM - so that's 17 to 23 oz, at 150 oz/gallon = about 17 oz by volume - I used 32 - 153%. Yup, I'm a newbie.

I will be trying the "rag" rollers rather than foam - I'll bet they work better and are cheaper.

I agree that 1708 is much easier to work with, and I can really see the logic of just using it exclusively on deck (tops?) rather than CSM. I bought a bunch of both, planning to cut the 1708 into strips for lapping - so maybe I'll see if I can squeak out using the 1708 for at least one of the decks.

Thanks again everyone. I promise to get some pictures up shortly.

 

[jbcurt00]

If you have a hard time w/ the MEKP ratios, switch to the metric system, at 1-2% MEKP

100ml of resin uses 1.5ml of hardener, down to 1% (1ml) if temps are high, and up to 2% (2ml) if temps are low.

50ml at a 1.5% catalyst rate uses 0.75ml of MEKP hardener.

Sounds like you've gotten the hang of laying the CSM, congrats

 

[MTboatguy]

That is why, I asked about Temp and Humidity, because your ratios will vary a bit based on those two numbers I have a buddy that sprays up the hulls for a boat manufacture for a living and the biggest electronic sign they have in the shop, shows only two things, temp and humidity and he is the lead spray/mix person and varies it daily based on those two numbers.

It takes some practice, but it sounds like you are getting the hang of it.

 

[Quantumn]

Nice to hear your plugging away now. It does take a little bit of practice to lay csm, but once you have it, you will be quick like a bunny :hippie:

 

[gm280]

Initially I was trying to figure out the percentages of MEKP to use as well. And my first mixture was so weak with the amount of MEPK I used that it literally took three days to cure. So after a few more experiments, I bought a bottle to use for getting the mixtures perfect every time. Now I mix to the metric system and it goes easily and perfect cure times as well. Here is a picture of that MEKP measuring bottle...

If you buy one of these measuring bottles and use the metric measurement system, you can get the perfect amount of MEKP to use instantly and no more wondering... For instant, if you want to mix up 700ml of poly resin, you squeeze the bottle 'til it fills to 7ml mark and pour it in the poly resin mixing container then stir/mix. You will then have a 1% mixture ready to use. Can't get any more easier then that. :thumb: