Sikoflex removal?

[sunquest]

I have 3 off D ring handles fitted to my lazaret and transom ladder covers which need replacing. The problem is removing them. They are fitted using screws and also some type of Sikoflex. I cannot prize them out as they are recessed into the grp and any attempt would damage the surrounding grp.
Maybe, if I drilled a hole through the handle and grp.enlarged the hole on the grp side, fitted a nut and bolt to effectively create a puller and progressively tightened up to draw it out.
Would this damage the grp under the handle?
Would using a heat gun soften the sikoflex?
Or is there a sikoflex remover or any other suggestions please.

Thanks Geoff

 

[boatmike]

Common problem. People use Sikaflex for everything! It's impossible to remove other than mechanically and there is no solvent for it once cured. Heat won't make a lot of difference but might help a bit. Other than brute force I can't suggest anything... Sorry! Been there done that and know all the swear words....

 

[SAWDOC]

I have 3 off D ring handles fitted to my lazaret and transom ladder covers which need replacing. The problem is removing them. They are fitted using screws and also some type of Sikoflex. I cannot prize them out as they are recessed into the grp and any attempt would damage the surrounding grp.
Maybe, if I drilled a hole through the handle and grp.enlarged the hole on the grp side, fitted a nut and bolt to effectively create a puller and progressively tightened up to draw it out.
Would this damage the grp under the handle?
Would using a heat gun soften the sikoflex?
Or is there a sikoflex remover or any other suggestions please.

Thanks Geoff

Have you removed the screws and attempted to prise the fittings up off the Sikaflex using a screwdriver or similar?

 

[sunquest]

Have you removed the screws and attempted to prise the fittings up off the Sikaflex using a screwdriver or similar?

Yes, I actually tried a 1" chisel to get into the recess to minimise damage to the grp but the gap is so small I couldn't get any leverage.

 

[SAMYL]

Can you cut the Sikoflex carefully with a scapel or end of a fine hacksaw blade?
Cellulose thinners will soften it a bit but it takes ages and has to be almost immersed in the thinners

 

[kieronriley]

get a length of mig welding wire, heat it,wrap it around screw head between hull and screw head and pull together ,i think i would use gloves,but it does work,Kieron

 

[SAWDOC]

Yes, I actually tried a 1" chisel to get into the recess to minimise damage to the grp but the gap is so small I couldn't get any leverage.

It is a little hard to visualise - Could you post a pic to illustrate? I know I had a similar issue when resealing a leaking stanchion base and with patience and a gently does it approach I did succeed in lifting the fitting using a paint scraper with a 1" width.

 

[mikesyam]

I would try the steam off a wall paper stripper, when I had a garage we repaired a radiator once with it and it was great until it got really hot then the heat softened its bite and the bracket fell off, worth a try.

 

[boatmike]

I would try the steam off a wall paper stripper, when I had a garage we repaired a radiator once with it and it was great until it got really hot then the heat softened its bite and the bracket fell off, worth a try.

No No No No!!! That amount of heat will damage the Gel Coat.....

 

[sunquest]

It is a little hard to visualise - Could you post a pic to illustrate? I know I had a similar issue when resealing a leaking stanchion base and with patience and a gently does it approach I did succeed in lifting the fitting using a paint scraper with a 1" width.

Sorry Sawdoc, Not near the boat for a while but imagine a plain lazaret cover, the D ring handle is 3" x 2" in size and is indented into the grp so it is flush. Therefore to use a screwdriver is too thin for leverage and would damage the surrounding grp, a chisel is too thick to get under the handle, but a sturdy thin scraper may just get in and under the handle. Thanks for your help.

Samyl. Thanks but not enough room to get a blade or similar underneath without snapping it.

Thanks kieronriley, can't see that working in this case. Might be able to screw a self tapper into the metal handle and lever up!

Thanks Boatmike. I think you are right, a little judicious brute force and ignorance, coupled with a paint scraper, self tapper and if necessary my original nut and bolt idea.

 

[GrahamHR]

Contrary to common belief, there is solvent that will dissolve fully cured polyurethane; dimethyl formamide. On immersing the PU in it, it will cause the PU to swell and become a weak gel. DMF is horrible stuff though and I doubt it's available to anyone but a licensed industrial / laboratory user ( it was/ may still be used in printing, the effects on people exposed to it are well documented!).

There are commercially available "PU dissolvers" based on N-methyl pyrrolidone ( "NMP") that are used in the PU industry for cleaning moulds; not as effective ( or nasty!) as DMF though .

Graham

 

[EastCoastChris]

Heat does work really well at softening it up. I have a DeWalt heat gun with a variable dial to set the temperature rather than just a couple of overly hot settings.

It goes cool enough that I can keep my hand in the way. You only need to get the Sikaflex good and warm to soften it enough. Think GRP exposed to hot sunny day type temperatures.

Chris

 

[jwdorst]

Diesel, at least theoretically, will soften Sikaflex. Perhaps enough to allow some movement of the fitting, thereby enabling the use of a thin blade to cut through the Sikaflex.

 

[SAWDOC]

Had a look at my copy of Pat Manley's "Simple boat maintenance" which guided me when i was renewing the stanchion base mentioned earlier. PM writes that Thinners No 9 can be used to soften "the sealant" He does not specify Sikaflex but in all likelihood, looking at the pics in the book that is what he is talking about. He does advise trying a little on a small area first to see how you get on. The same advice would probably apply to the heat gun option which should help once you keep a good eye on how it is affecting things.

 

[charles_reed]

I have 3 off D ring handles fitted to my lazaret and transom ladder covers which need replacing. The problem is removing them. They are fitted using screws and also some type of Sikoflex. I cannot prize them out as they are recessed into the grp and any attempt would damage the surrounding grp.
Maybe, if I drilled a hole through the handle and grp.enlarged the hole on the grp side, fitted a nut and bolt to effectively create a puller and progressively tightened up to draw it out.
Would this damage the grp under the handle?
Would using a heat gun soften the sikoflex?
Or is there a sikoflex remover or any other suggestions please.

Thanks Geoff

SIKAFLEX 208 TECHNIQUE REMOVER 1 LITRE
SIKA 205 TECHNIQUE CLEANER 1 LITRE

There are a wide range of Sikkens adhesives and sealants (all sold to the gullible at vastly inflated prices) - assuming you are referring to their polyurethane sealant one of the above will do the job.

 

[boatmike]

SIKAFLEX 208 TECHNIQUE REMOVER 1 LITRE
SIKA 205 TECHNIQUE CLEANER 1 LITRE

There are a wide range of Sikkens adhesives and sealants (all sold to the gullible at vastly inflated prices) - assuming you are referring to their polyurethane sealant one of the above will do the job.

I believe if you look at the tech specs of these products they are intended for cleanup BEFORE the product has cured not after.

 

[webcraft]

.
If you want to clean up Sikaflex before it has cured use baby wipes (lots of them).

- W

 

[SAMYL]

Is the handle still intact? Why not put a bar through the handle and lever against a block of wood. The sikaflex will fail before the GRP so dont worry. GRP is easily repaired. A good hard short dunt should do it especially if you can get the bar near to one end of the plate.

 

[boatmike]

Contrary to common belief, there is solvent that will dissolve fully cured polyurethane; dimethyl formamide. On immersing the PU in it, it will cause the PU to swell and become a weak gel. DMF is horrible stuff though and I doubt it's available to anyone but a licensed industrial / laboratory user ( it was/ may still be used in printing, the effects on people exposed to it are well documented!).

There are commercially available "PU dissolvers" based on N-methyl pyrrolidone ( "NMP") that are used in the PU industry for cleaning moulds; not as effective ( or nasty!) as DMF though .

Graham

Interesting.. Can you say that the same solvent will not attack Gel Coat though??? Many solvents (such as conventional paint remover) will certainly have an effect on Polyurethane but also have a detremental effect on gel coat. The trick is to attack the Sikaflex without melting the boat!

 

[boatmike]

Diesel, at least theoretically, will soften Sikaflex. Perhaps enough to allow some movement of the fitting, thereby enabling the use of a thin blade to cut through the Sikaflex.

I have heard this one before and have indeed tried it but it didn't work. I think it's one of those urban myths that often gets repeated but doesn't work. At least in the short term. Over a very long period I have seen engine mounts part company with the steel they were bonded to blamed on exposure to diesel so it might well work in theory as you say. In practice however you need something pretty aggresive to get an adhesive bond to break down as you can only in practice get anything in contact with the outer edges.

I hesitate to suggest it but the only way I have got such a fitting off before is to get the fitting hot enough to "burn" it off the Sika underneath. You need to get it very hot very quickly though. I used an oxy-acetylene torch. That works, but you need to ensure you get the fitting hot and leave the Gel Coat cool so a normal blowtorch won't work.

Thinks???? I wonder what would happen if you made up a steel baffle plate with just the shape of the fitting cut out of it laid it over the GRP to protect it and then hit it with a blowlamp???? Risky but it might work......