Advice from Gelmaster please?

[rafiki_]

I have some crazing where the decking meets the radar arch. It covers an area of about 8" by 4". Clearly the 90deg angle deck to arch is not easy to address. It does not appear to be growing.

My usual maintenance man says not to worry, I'll do more harm than good addressing this.

Your views please?

 

[Gelmaster]

I have some crazing where the decking meets the radar arch. It covers an area of about 8" by 4". Clearly the 90deg angle deck to arch is not easy to address. It does not appear to be growing.

My usual maintenance man says not to worry, I'll do more harm than good addressing this.

Your views please?

It would definately be a good idea to have the stress cracks treated.
Moisture will eventually creep in, which might eventually weaken the affected area even more!
Dont panic though, as it isnt as if it is a hull/hydrolisis problem!
If its not too unsightly, i am sure it wont cause you any immediate problems.

But yes, always best to sort it out.
If you do decide to postpone treatment for now (which shouldnt be a problem), simply rub a silcone based wax "hard" into the fractures, and buff!
This should hold most of the moisture back for the time being, until a proper
repair can be carried out!
Because of the location of the fractures, it would be an absolute nightmare to reinforce the underside of the GRP, which just might be the answer,
but i would simply repair the surface cracks primarily,
and " IF " they did return, then reinforcement to the GRP is probably the answer!
I have a feeling, that repairing the fractures alone would suffice!!
Just keep a close eye on it to make sure it isnt getting any bigger, but i wouldnt worry too much about it !

 

[oldsaltoz]

I have some crazing where the decking meets the radar arch. It covers an area of about 8" by 4". Clearly the 90deg angle deck to arch is not easy to address. It does not appear to be growing.

My usual maintenance man says not to worry, I'll do more harm than good addressing this.

Your views please?

G'day Rafiki,

You have stress cracks because the deck is flexing, perhaps someone uses the bar to board to boat?

A simple way to reinforce areas with limited access is to make up a stainless steel plate to fit the holes drilled through the base; mix some resin and micro fibres and butter on the top side of the plate with a slight peak in the middle, this should help push the air to the the outside. Tighten only with your fingers and leave to cure, make sure you have a least 3 mm thickness between hull and plate.

Next day tighten the nuts and you are done.

Good luck.

PS. I would apply any silicone to any part of the boat, it can be very hard to remove and 'Nothing' will stick to it.

 

[Gelmaster]

Silicone wax pushed into the hairline cracks is "not" a problem at all!!
when the gelcoat repair commences, the cracks will have to be routered back as deep as necessary, and thouroughly cleaned with acetone before the fresh gelcoat is applied.

But the stainless plate is a good idea!

PS............I repair this sort of problem every week !!

 

[rafiki_]

Many thanks for the advice. What is the best tool for routing out the cracks. How do you get a gelcoat colour match?

 

[Gelmaster]

Many thanks for the advice. What is the best tool for routing out the cracks. How do you get a gelcoat colour match?

I use a dremmel router with a round bit (about 4mm radius head)
Stick it in to start, then pull through the hairline crack in one sweep!

Colour matching is an art.... I have the primary (polyester based pigments) and play around. Usually takes me about 2 hours to match.
Red, Blue, Yellow, Black & a Beige!!!
I start with Scott Bader white gelcoat!!
If the colour is anything but anything that resembles white, then i start with a clear gelcoat..ie Green, red or blue usually the culprits !

Plenty of Acetone on hand to clean the area before the desired match is applied !

 

[rafiki_]

Thanks Gelmaster. The gelcoat is white, so any tips on matching?

 

[gjgm]

Thanks Gelmaster. The gelcoat is white, so any tips on matching?

Yep, realise that it isnt white !
If you buy trade quantities rather than thimble quantities, there will plenty to experiment with. Have plenty of paper coffee cups and wooden mixers, as you need clean one each time.
Sand around the repair area with 1200 wet and dry to get back to the clean gel. Maybe get a colour wheel if you have no idea how to mix colours. If it takes Gelmaster two hours to match, it gives you a clue as to how long its going to take an amateur!!
Start with a tablespoon on the basic gel, and add a tiny tiny drop of your selected pigment (s), mix up, and smear (no hardener) onto the clean gel to see how it matches. Wipe clean off with acetone. Then you just keep playing with the pigments until you are happy.
First half hour you might learn at least which pigments to use, and which not to use. The its down to experimenting with the quantities, until you get it right. AFAIR, black turns the colours greyer,it doesnt darken them, for example. Wheres as I think the red did darken the colour. Not obvious, and might only apply to the colour I was matching.
Last time I did it, I reckon it took me 3-4 hours to match it. It was a nice warm sunny day, blue sky, and the whole experience was quite fun.
Might not be fun at 10 degrees with a wind howling about. Its a slow game.

 

[rafiki_]

Is there a commercial colour matcher out there, as there is for cars?

 

[gjgm]

Is there a commercial colour matcher out there, as there is for cars?

Dont think so,partly I reckon because you are not going to re-gel one side of the boat etc, to blend in, like you do with a car. You need to match to your old gel as it now is, not what was originally put on.You might re-do a small area surrounding the repair, at most. Gel will need to be sanded back and polished; imagine sanding back one side of a boat ! I dont know, but I would guess weeks of labour! Thats why on big repairs and older boats its often more cost effective to paint.
Bear in mind that new and old gel will change colour at different rates due to UV and grime etc. Probably ok for a couple of years maybe, but it wont remain invisible for ever. Blue seems visible after about an hour sometimes, it seems to me , and thats even matching with factory matched gel !
Some pros can do it extremely well, but I have had others just refuse to take a job. With factory matched its usually pretty good, but lets be honest, otherwise it is a craft.
Lastly, unless you set up full protection for the reapir area, and provide a suitable temp for the whole repair area, or can move into a warmed workshop etc, you are running out of good weather. 20 degrees is good; cant see that for a good 6 months. Its not the only temp that works, but forget it at 10 degrees.

 

[oldsaltoz]

As others have pointed out getting the colour right can be a problem and knowing it will age and show up again is a disappointment.

However, if when sanding the area to start with you collect the dust and mix this with the new material you will be on the way to a match and know that the older material will fade at much the same rate as the existing gel coat, it's not perfect but it helps the new gel coat colour match last a bit longer.

Good luck.

 

[gjgm]

As others have pointed out getting the colour right can be a problem and knowing it will age and show up again is a disappointment.

However, if when sanding the area to start with you collect the dust and mix this with the new material you will be on the way to a match and know that the older material will fade at much the same rate as the existing gel coat, it's not perfect but it helps the new gel coat colour match last a bit longer.

Good luck.

Might help, but wouldnt you need an aweful lot of dust? Also, you are not going to get a mirror like gel finish if your new gel is full of dust/grit and muck !
Actually one idea might be to make the repair area delibertely different, by masking of an equal square/rectangle on both sides of the boat. IE, make it obvious, rather than a naff colour match...even a different colour?