Gluing down solar panales

[JumbleDuck]

I have two nice semi-flexible solar panels to attach to my coachroof. The current ones are held on with velcro, which made changing them easier, but the news ones are very much better and so changing them is a minor but non-zero concern. Also, the velcro always went manky.

I've been toying with all sorts of ways of fastening them down. They only have holes in the corners, which isn't enough to hold them down in the middle, and drilling more is not at option. The easiest solution would be simply to stick them down, but it has to be with something which can, if necessary, be undone. I think that rules out Sikaflex (does it?) and so would welcome any other suggestions.

The coachroof has a basket-weave non-slip pattern moulded into it, so reasonable gap filling is essential.

Plan B is to hold them down with a teak batten along each side, held down by screws through the corner holes.

 

[Boathook]

I stuck my semi flexible panels down on my wheel house roof with an adhesive sealant. I can't remember what type, but it might have even been white waterproof no nails. The panels (spectra?) had holes with grommets in each corner and I allowed the adhesive sealant to fill the holes. One has been in place for around 5 years with no problems so far. I did consider drilling holes and bolting in place but it was more holes that would possibly leak, etc.

 

[tillergirl]

Polysulphide.

solar panels ext by Roger Gaspar, on Flickr

Can retain the slight air circulation underneath that semi-flexible require and can be lifted without damage - albeit needing care.

 

[Ningaloo]

Polysulphide.
Can retain the slight air circulation underneath that semi-flexible require and can be lifted without damage - albeit needing care.

Can you explain this please as it sounds like exactly what I need too?

I previously used a mastic which did a great job of securing the PV panel but didn't leave an air gap to reduce heat build up. It would also be impossible to remove the panel without destroying it.

I am about to fit a large panel to my new boat and this will cover the screws that hold the hatch slide in place. I didn't need to remove this component in 6 seasons on the previous boat, but sods law...

How does polysulphide differ from other mastics?

 

[Moodysailor]

It's a tricky one as the best solution is probably the one you are trying to avoid.

If you are happy with the panel location, and the only issue is that you may need to replace the panels like-for-like (or upgrade) in future, then I would probably be tempted to glass in a few fixed mounting points with blind nuts or bighead nuts. Fully watertight, but removable when needed.

Alternatively, an adhesive sealant will work just fine. If the only time you will need to remove it is when the panels die in 5+ years, then it's not an issue as you can use a multi-tool to cut through the adhesive 'blobs' then. So in that case, a polyurethane would be OK (we used Stixall recently for some repairs, cheap, lower shear strength and higher elasticity than Sika and no complaints so far)

 

[peteK]

I used butyl strip around circumference of panel only so easy to remove.

 

[Dunx]

I did ours with 3M very high bond tape. This was for a couple of largish semi flexible panels (120w) onto checkered GRP. It has survived 12 months of weather on the Clyde with no sign of it letting go. It is quite expensive but my logic was that as a tape I had a better chance of removing it from the GPR if needed than a proprietary glue. Pleased so far.

 

[agurney]

I've happily used silicone sealant for mine.
However, the company I work uses an industrial 3M velcro-type product called DualLock to attach equipment to various surfaces, and I've used it successfully on the boat.

It's a single-sided hard plastic comb that interlocks with itself, for indoor and outdoor use, and the adhesive is pretty robust. The joint tends to be stronger than the adhesive!.

 

[JumbleDuck]

Thanks, everybody ...

Polysulphide.

Boatlife Lifecalk polysulfide used to be my go-to for everything ( I think it did more to hold the keen onto my Jouster than the bolts did) but hasn't been available in the UK for years. Have you an alternative suggestion, and does it smell a bit too?

It's a tricky one as the best solution is probably the one you are trying to avoid.

If you are happy with the panel location, and the only issue is that you may need to replace the panels like-for-like (or upgrade) in future, then I would probably be tempted to glass in a few fixed mounting points with blind nuts or bighead nuts. Fully watertight, but removable when needed.

Alternatively, an adhesive sealant will work just fine. If the only time you will need to remove it is when the panels die in 5+ years, then it's not an issue as you can use a multi-tool to cut through the adhesive 'blobs' then. So in that case, a polyurethane would be OK (we used Stixall recently for some repairs, cheap, lower shear strength and higher elasticity than Sika and no complaints so far)

The problem with the mounting points - if I follow your suggestion - is that the panels only have holes at the corners and so the middles tend to lift up a bit, allowing flutter, critters and so on. I've used PU with great success before - it holds the LPG venturi onto th ecarburettor of my Citroën DS beautifully.

I used butyl strip around circumference of panel only so easy to remove.

Is it good and sticky? The panels are quite stiff (Sunbeam Solar Tough series) and will need fair downforce to hold them in place.

I did ours with 3M very high bond tape. This was for a couple of largish semi flexible panels (120w) onto checkered GRP. It has survived 12 months of weather on the Clyde with no sign of it letting go. It is quite expensive but my logic was that as a tape I had a better chance of removing it from the GPR if needed than a proprietary glue. Pleased so far.

Something like this?

Looks very possible, and easier to apply than squirty stuff.

I've happily used silicone sealant for mine.
However, the company I work uses an industrial 3M velcro-type product called DualLock to attach equipment to various surfaces, and I've used it successfully on the boat.

It's a single-sided hard plastic comb that interlocks with itself, for indoor and outdoor use, and the adhesive is pretty robust. The joint tends to be stronger than the adhesive!.

I'm a great fan of velcro, but found that after a couple of years the stuff holding the panels down was - though still working - completely full of green slimey stuff. Since I don't plan to take the panels off unless I have to replace them (duplicate set bought just before the Brexit axe fell on supplies) I'm happy to trade more longevity for less slime.

Overall I think the 3M tape is winning, particularly if Largs Chandlers sell it ... further advice very welcome though.

 

[Dunx]

That’s the stuff Jumbleduck. I sourced mine on eBay and yes dead easy to apply. I’m not sure I have ever seen it in a chandler. I wiped the GRP and panel backs over with an alcohol thinners before application just to ensure a clean surface.

 

[LittleSister]

I've been looking into this for a while.

The instructions for one of the better documented panels (forgotten name) suggests putting thin stripes of glue longitudinally up/down the slope they are on (I imagine something like 5mm wide beads of glue, spaced at about 50mm apart). This allows any water to drain and avoids trapped air forcing the panel to bulge up in hot weather. (It is necessary to carefully put weight on the panel so that conforms to the curved surface until the glue has set.) One could do something similar if adhesive tape were used.

Like you, I think, I'm keen to find an adhesive which has sufficient grip to securely hold the panel, but which can be removed from the GRP should the panel be removed and not replaced in future. (Though in my case the GRP is smooth, rather than patterned.

I was leaning towards 'CT1', in part because they also sell a remover, called 'Multisolve'. I'd appreciate any comments on those from anyone who has used those.

p.s. I've belatedly found today's thread specifically about CT1 - CT-1 sealant/adhesive

 

[V1701]

If you want an air gap underneath how about cutting some wooden discs, bond them to the mounting surface then bond the panels to the wooden discs? I would use CT1 or OB1, coincidentally there is a CT1 thread running on here at the moment as well, it's brilliant stuff used it for years for allsorts...

 

[tillergirl]

By all means use CT1 if you are happy to mechanically remove it when you want the panel changed. Being an adhesive you will suffer some damage on the surface of the substrate but presumably you would cover the damage with some new panels in the future. Polysulphide will retain and secure the panels - note that the panels have stayed in palce for 3 years so far. And if necessary to replace them, it will be possible to remove the panels without any solvent. The bead of polysuphide can provide sufficient air and moisture gap underneath. You can get polysuphide at Polysulphide Mastic Sealants Sealants Online - or www.countyconchem.co.uk. Both stock the Arbokol which is an excellent product.

 

[peteK]

Plenty sticky is butyl strip in fact you have to cut through the sealant to remove them,I used a wallpaper scraper.

 

[wully1]

Hot melt glue gun if you must stick it down? Hot Air gun will soften the glue if you need to remove the panel. I use it to glue in my arrow points, not sure how well it will work over a large area though.

My new panel is bungied onto the loops I had built into the sprayhood . The panel only came with holes in the 4 corners so I (carefully) drilled another two holes in the middle on the plastic strip round the outside of the cells, remembering to seal round the holes with some gloup who’s name escapes me.

 

[sgr143]

I did ours with 3M very high bond tape. This was for a couple of largish semi flexible panels (120w) onto checkered GRP. It has survived 12 months of weather on the Clyde with no sign of it letting go. It is quite expensive but my logic was that as a tape I had a better chance of removing it from the GPR if needed than a proprietary glue. Pleased so far.

I'm thinking of fitting a panel on the hatch "garage" top. It has a crinkly sort of non-slip moulding. I had been thinking about the heavy-duty double-sided tape - having used something similar for holding a replacement wing mirror in place (nothing's shifted after now 3 years or more with that). My slight worry is the squidgy middle layer of the tape (about 1mm thick?). Would it give way locally enough, if a foot was placed (say) on the middle of the panel, to allow enough local bending of the panel to cause it to break?
If in any doubt I might use screws at the corners with a thin layer of sealant round the edges instead.

 

[thinwater]

I've happily used silicone sealant for mine.
However, the company I work uses an industrial 3M velcro-type product called DualLock to attach equipment to various surfaces, and I've used it successfully on the boat.

It's a single-sided hard plastic comb that interlocks with itself, for indoor and outdoor use, and the adhesive is pretty robust. The joint tends to be stronger than the adhesive!.

This. I have used it for many things with good success. Not at all like normal Velcro. It actually "clicks" when mated, and a slight twist with a screw driver or similar is often needed to break the bond.

 

[AngusMcDoon]

I have just completed sticking down floor laminate with 3M double sided adhesive sheets. Once down, it's going nowhere. I stuck them to a smooth surface, but I accidently dropped a slither onto my textured cockpit floor, and so far, that's not going anywhere either! 3M says it's waterproof and attempts to remove my stuck bit with water achieved nothing.

3M™ Acrylic Adhesive Transfer Tape 467 (7952MP)

If you want to try it send me a PM and I'll stick a sample in the post to you.

 

[Never Grumble]

I have just completed sticking down floor laminate with 3M double sided adhesive sheets. Once down, it's going nowhere. I stuck them to a smooth surface, but I accidently dropped a slither onto my textured cockpit floor, and so far, that's not going anywhere either! 3M says it's waterproof and attempts to remove my stuck bit with water achieved nothing.

3M™ Acrylic Adhesive Transfer Tape 467 (7952MP)

If you want to try it send me a PM and I'll stick a sample in the post to you.

I'm also about to stick down a flexible solar panel, if I use tape how will I remove it in the future? if that becomes necessary?

 

[AngusMcDoon]

I'm also about to stick down a flexible solar panel, if I use tape how will I remove it in the future? if that becomes necessary?

As I discovered when I stuck a bit of flooring in the wrong place, you can pull it up, but it destroyed my carefully shaped bit of flooring, as it probably would a solar panel. I don't think the bond is as strong as sikaflex that can rip up gelcoat. The glue layer is very thin, so if you were relaying new panels you could probably stick it straight over any residual glue.

I'm working on a solvent to get the sticky bit off my cockpit floor...