Boarding out our deck for tanked balcony this afternoon. Had to give up as just too damn hot, no shade, no breeze. Forecast is for 25-27c all week, little cloud, no breeze.

 

Did a quick Google and apart from using less catalyst, any issues with fibreglassing in this weather? With the direct sun I'm sure surface temp will be 40c+ as direct south facing and sheltered 

Edited June 11, 20233 yr by Conor

11 minutes ago, Conor said:

Did a quick Google and apart from using less catalyst, any issues with fibreglassing in this weather? With the direct sun I'm sure surface temp will be 40c+ as direct south facing and sheltered

Will give you problems as too little catalyst (really an oxidant) will stop proper cross linking of the monomers.

You can get different hardeners to get round this problem.

Your biggest issue will be UV light, that caused the top to react and cure faster, this stops the excess styrene evaporating away.

If you can be sure it will be dry early morning, that is the time to do it.

Thanks.

 

For the catalyst it's a pre assembled kit so don't think there's much choice, but I'll speak to the supplier today. Was just thinking using 1% catalyst rather than the usual 1.5-2% I would have used previously. 

 

I'll try and get most of the work done in the mornings to avoid the direct sun.

EDPM superior in every way including fitting, the warmer it is the softer the rubber!

12 minutes ago, Dave Jones said:

EDPM superior in every way including fitting, the warmer it is the softer the rubber!

How much will it shrink by when it is -10°C.

24 minutes ago, Dave Jones said:

EDPM superior in every way including fitting, the warmer it is the softer the rubber!

Except for the aesthetics. 

6 minutes ago, Canski said:

Except for the aesthetics. 

Looks like a rubber sheath.

 

I just looked up the thermal expansion figures.

 

GRP is 25x10^-6 m/m.k

EDPM 160x10^-6 m/m.k

That is nearly 6.5 times the movement.

+1 for GRP but not in this weather.

its virtually guaranteed grp will movement fail before EDPM.

 

EDPM also greener being a recycled product.

7 hours ago, SteamyTea said:

I just looked up the thermal expansion figures.

 

GRP is 25x10^-6 m/m.k

EDPM 160x10^-6 m/m.k

That is nearly 6.5 times the movement.

 

who would have though rubber was stretchy. lol

1 hour ago, Dave Jones said:

 

who would have though rubber was stretchy. lol

Thermal expansion and contraction is not elasticity.

 

EPDM was my first choice, but the only local company I could find that sell it, turned out to be beyond useless. And I could not find anybody willing to ship to northern ireland. Also was working our far more expensive, and at this stage in our build, that's hugely important 

 

I've done a GRP roof before, and was shown how to do it properly by a guy that builds GRP boats. This roof will not fail.

1 hour ago, Dave Jones said:

its virtually guaranteed grp will movement fail before EDPM.

A very bold claim, you must have evidence to back it up, shame you won't share it publicly to help others make informed decision. 

2 minutes ago, Conor said:

I've done a GRP roof before, and was shown how to do it properly by a guy that builds GRP boats

Excellent.

I started off working in a boat builders, then moved on to vehicle parts and finally steam cabins.

Steam cabins are used for rapid aging of coatings and materials, you don't want your test equipment failing before the test sample.

6 hours ago, SteamyTea said:

A very bold claim, you must have evidence to back it up, shame you won't share it publicly to help others make informed decision. 

 

the lads who did ours commented on how many newish grp roofs they are replacing due to cracking. could be they were all poorly fitted. EDPM much more forgiving in every respect. Not to mention its green as well.

2 minutes ago, Dave Jones said:

could be they were all poorly fitted

Could be.

I have done well over a million miles in my cars, last month I lost a wheel nut. Probably got missed when the tyre was changed. If it happened most times at that tyre centre I would question their ability, but once in over 45 years, just one of those things.

Properly done, GRP will outlive a person.

 

I don't think you can claim that any building material is 'green', without first defining, with data and evidence, what you mean by 'green'.

At nearly 80 kg CO2 per square metre, not exactly low carbon. 

http://rubberbond.co.uk/sustainability-of-epdm/

 

GRP is 0.08 kg CO2/kg.

https://www.steponsafety.co.uk/grp-sustainability/

That works out at around 0.4 kg CO2/m².

 

 

google recycled. 

So was up at 5.30am this morning... Job done

5 minutes ago, Conor said:

So was up at 5.30am this morning... Job done

Pictures please.

And not just of your sticky fingers.

Not until the top coat is on and flashings on! All you can see is the OSB deck through the grp. Which means it was done right I suppose.

 

I did 2% catalyst when it was still cool, down to 1.75% when the sun started hitting. Had about 15mins working time only. Few spots it got away from me that resulted in a few lumps and bubbles. Will need a bit more work. Many rollers and brushes in the bin now.

10 minutes ago, Conor said:

I did 2% catalyst when it was still cool, down to 1.75% when the sun started hitting. Had about 15mins working time only

There are very few job that once started, you really cannot stop, resin work is one of them.

As you can see the OSB though the GRP, it seems like you went for a resin rich layup, which is a good thing.  I am sure you can sort the lumps and bumps out easily enough with an angle grinder and some extra mat/resin.

 

A topcoat always makes thing look better.

Edited June 16, 20233 yr by SteamyTea

1 hour ago, SteamyTea said:

There are very few job that once started, you really cannot stop, resin work is one of them.

As you can see the OSB though the GRP, it seems like you went for a resin rich layup, which is a good thing.  I am sure you can sort the lumps and bumps out easily enough with an angle grinder and some extra mat/resin.

 

A topcoat always makes thing look better.

2.5kg m² rather than the reccomended 2kg.

 

That is very resin rich. Good job Conor. Plenty of sweat drips mixed in with that resin i bet.

There were indeed. Was swiftly off to the pub for three pints of reward bitter shortly after.