More transom problems, need some advice

[zymox]

Hello again m8's

Today I did some serious grinding


and found out that there was a couple of big air-pockets from the manufacturing.


I grounded it down to smoothen out the edges but now it feels and looks like a soft moon-landscape..
Can I just add two layers of 450g CSM and attach my transom-core or do I have to fill the air-pockets before and then use some PB-Mix?

Also I found alot of blisters containing really clear water? and a crack going all the way from port to starboard along the edge between the transom-skin and the hull that I grind out almost all the way out to the gel-coat. How do I go from here, can I go with PB-Mix or I have to replace the laminate with new CSM strings before I attach the transom-core?

this is one of the corner still to be grind out , have to with a power drill here since the angel grinder can't.

Thanks in adv. & BRGDS

 

[ondarvr]

Re: More transom problems, need some advice

Small voids can be filled with putty, the cracks you exposed need to be repaired with glass, and not just CSM though. You should use roving or 1708 to build the surface back up again and since it cracked you may want to build it back with a little more glass than was there before.

 

[zymox]

Re: More transom problems, need some advice

ok, I can't find that 1708 here in Sweden but have seen a lot of videos with it... would love to try it out.
I guess I have to get some roving also then.

Why is it that I can't use CSM only? I mean the roving has it strength in vertical and horizontal directions and the csm in all directions?

 

[ondarvr]

Re: More transom problems, need some advice

CSM is a good product for certain applications, but it has far less strength than either roving or 1708, it has to do with the short fiber length and high resin content of CSM. A 1708 or roving laminate holds about 50% resin, A CSM laminate holds about 70% resin, resin itself has little strength, so the higher the resin content the weaker the laminate.

 

[zymox]

Re: More transom problems, need some advice

Aha, Thank you very much for your answer, Feels good to learn something everyday
On the other hand, when I now do see your answer I should have been able to figure that out my self...

Anyhow, I can get the hold of 300g/m2 roving and I have a lot of 450g/m2 CSM.
How do you recommend me to laminate?

1 layer 450g/m2 csm and then 1 or 2 layers of roving and so on until I feel that I'm good?

My plan after your answer is:

I will start with strings sizing bigger and bigger to fill up the cracked area and then apply some PB-Mix to the surface just to get a 100% contact with the transom-cord and then I will skin all up with a 2 or 3 layers of 1 csm + 1 or 2 roving layer.
The transom-core will be 2 or 3*18mm plywood - 13 layers. water resist glue.

How does that sounds for a transom repair?
The sign says year 1966 : 150hp Max on the original approx. 26mm plywoodcore.

I'm planning on a 140hp looper for this transom so I'm terrified that something is going the wrong way...

 

[GT1000000]

Re: More transom problems, need some advice

Hello zymox,

I will let the experts give you the advice on the proper materials and procedures.

I just want to say welcome to the iboats drydock and PLEASE, get some cheap goggles to cover your eyeballs...besides fiberglass not being too awful friendly with your skin and lungs, it is still tiny bits of ground up glass that will, at the very least irritate the living heck out of your eyes and could scratch the crap out them enough to cause irrepairable damage...

Wouldn't want to have a blind man trying to navigate a freshly restored boat, would we???

Best Regards,
GT1M

 

[zymox]

Re: More transom problems, need some advice

Actually I can't agree with you more than I do, really. Thanks for the concern.
I tried to use goggles today but it took about 20 sec. for them to be totally messed up with dust and when I tried to hunt a crack thin as hairline I just couldn't stand it... I know this is no excuse and I will for sure be more careful in the future.

BRGDS Zymox

 

[oops!]

Re: More transom problems, need some advice

hi zymox

looking at the first pic.......i am itching form here. ....actually.....if we could keep that photo here at i boats we would make you the poster boy for "what not to wear for safety gear during grinding"...lol

the dust mask you are using is woefully inadequate bud.....please read this http://forums.iboats.com/showthread.php?t=235651

ok.....to laminater the layers of glass......start your first with 2 layers of csm.....then one layer of woven.....then another csm. never lay woven over anything without csm....between any layer of woven there must be csm.

follow those basic glassing rules. and you can build your thickness to what ever you want

cheers
oops

 

[zymox]

Re: More transom problems, need some advice

, I think I have to remove that picture...

I saw that mask you refer to the other day and believe that it's a solvent filter with dust-filterer on and thought that since the styrene is joined with the polyester it's only gonna be dust. I didn't read the text though... Now I did... "thoes little paper dust masks will not do the job...at all" :redface: When I do the lamination I use the same type with reactive carbon filters.

BTW: Thank you for your help and time in me, I really appreciate it.

 

[zymox]

Re: More transom problems, need some advice

5 More questions for you pro's,

1. I have done a replica of the transom-core as it was original and I wonder if I should stick with this or do I gain anything by doing it as drawn in the picture? (material as it is in picture is 2*18mm plywood 13-layers based on another tip I got here)

2. How much do I have to grind of the hull to make sure I get a really good joint between the inner transom skin and the hull?

Answer: 6 Inches (approx 15cm). Info found! , oops! #206

3. The other picture shows the new transom-core and my outer skin, how have you solved the problem I'm facing with the draining hole?

4. I tried clamping to day just for trying it out and I feel like I have to tighten the clamps A LOTS to get the skin in line with the core. Is this the normal procedure? I mean it feels when I dry mount everything like I will press all the resin out of there...

5. I did get a tip of making the transom core out of 2 layers 19mm plywood for the transom-core before and now that I can see the thickness of this I think it looks thin. Is this really the right size? I intend to use my 140 looper for this boat...

If I do a calculation of the work I intend to do I get something like this but I can be way out here:
Thickness of outer skin is 3mm + I will add 2 layers 450g csm 1 layer 300g woven and 1 layer 450g csm (approx. 2 mm) + the new core 36mm and last i will seal it all up with 2 layers csm + 1 layer woven + 1 layer csm + 1 layer woven + 1 layer csm 3-4mm
making it over all, if I have done the math correct 44mm ( includin the sealing and the bond layer it will be 1 & 3/4 inches)

 

[Woodonglass]

Re: More transom problems, need some advice

If you want the top cap to fit back on properly you must make the transom the exact thickness as the previous one. If she were mine I'd be troweling on some PB to smooth out that outer skin. Once it was smooth and hard, I would trowel the Peanut Butter onto the skin and the transom approximately 1/4" thick. this will yield 1/2" of PB use the clamps to apply Medium pressure, enuf for the PB to squeeze out around all the edges and fillet the edges. As for fabricating the transom, I'd put it back exactly like I found it.

 

[zymox]

Re: More transom problems, need some advice

More stupid questions from me

I found out to day that the csm fibers in loose weight is extremely hard to get here in Sweden at a reasonable price so I wonder what I can use instead to make a good PB-Mix ?

I can get putty with fibers but my experience with that is that it doesn't stick very well to anything and also the amount of fibers in it is way to little & to small in length.

I asked my local resin dealer and he told me he tried it once and never again, he didn't like it...
Use resin with microbaloons only instead he said. I don't really like his idea since I know how fragile the resin is when it's out of laminating-materials.

 

[Woodonglass]

Re: More transom problems, need some advice

You can get a sharp knife or scissors and make your own chopped fibers or just take scrap pieces and tear them to pieces and then cut them up into smaller pieces. I've done it a lot. Mix resin and cobosil and your torn up fibers and you've got PB!!

 

[zymox]

Re: More transom problems, need some advice

I just knew you would save me

Thanks M8, I thought about it but was suspecting I needed way more fibers than I can manage to peel for the rest of my life. After living in the telephone all day to day you just gave me the spirit back again.

Thanks

 

[zymox]

Re: More transom problems, need some advice

Hello M8's

Some progress is on the way now, Niicce and ofcourse some more trouble :redface:

Made water Proof

Added 2 layers of 300g CSM as bonding filler/joiner

Adding the inner ply layer

Happy with the laminate, hard to tell what is wood and what is the poly laminate.

Protected and ready for cleanup. One overlay of 300g CSM

 

[zymox]

Re: More transom problems, need some advice

Ohh, I forgot about the problem but here it is,


-> Trouble <-

What you see is what it looks like, alot of air!
Not in a critical area since it's the cap side of the transom but what do I do now and how do you guys do to get it wrapped around 90 deg. corners without the raising of the glas? I've tried just about everything...

Ohh, and one more thing for you, Happy new year to you all from Sweden

 

[ondarvr]

Re: More transom problems, need some advice

The edges need to be well rounded for the glass to wrap around the corners. Most of the time you can just leave the edges until the transom is tabbed in place, then its all covered easily

 

[Woodonglass]

Re: More transom problems, need some advice

You might try "Tearing the CSM with your hands" By ripping it it pulls the fibers and loosens them up make them easier to go over the corners. ondarvr is correct in that glass does not like sharp corners. You can cut "Cap Strips and Pre Crease them just like making a crease in your pants but I like tearing the glass better.

 

[zymox]

Re: More transom problems, need some advice

Thanks for your answers.

I couldn't hold my self today so I did actually grind out the air-bubbles and thought that it will be sorted out when I put it in place with all that PB. Laid a thicker mat on the side that is to be towards the outer transom skin and will be on my way tomorrow to lay up all the material I did grind out from the hull.

I have an issue with the PB though,
I tried to do some with glass micro balloons and my own chopped mat but I think I got the fibers to long since it looks like hair you pull out from the sink when it's clogged. and it felt pretty useless. approx. how long do I have to do the fibers?

I saw an example of how to mix it in one the most informative videos I ever seen where the guy "Frisco" something used fabricated fibers about 1/4" long so I think I will go with this length. But one thing I couldn't understand in the video though is how much fibers is good to go with. He showed up a jar with the amount of a full tablespoon and said especially that you should not use to much of it. Also he mentioned a pint of resin witch I believe is equivalent to about a half a liter. My wonder is if that small amount of fibers is enough for a pint or how much fibers is good to go with?

 

[Woodonglass]

Re: More transom problems, need some advice

Micro ballons are ok but cabosil is better for PB. 1/4" fibers is the right thing to use. The "Hairy PB" you made will work to but it is more of a structural mix but still it will work for filleting around the edges of the transom. As far as how much of the fibers to use Frisco is correct a heaping tablespoon per 1/2 liter of resin. Microballoons are typically use for fairing material since they make the resin easier to sand when it's cured.