Sikaflex Question

Rjcamper

Rjcamper

Joined
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Devon / Cornish border
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Mobilvetta Kimu 122
Exp
2019
After some advice, just purchased a Eco-Worthy Solar Panel Kit from Flebay, states corner / mid brackets are plastic.

Contacted Sikaflex and they want to know what type of plastic. As I can not confirm this they have recommended 552 + Activator 205, not the cheapest (£48 - 1 Tube + 1l of activator), but don't want to lose the panel half way down the M5 ;-)

What have others used? See some have used 221, I am not going to use screws etc, so just want to bond to the roof

Also best supplier - Toolstation / Screwfix do not list Sikaflex 552 / 221
 
When I contacted SIKA in 2018 asking for advice about fitting Solar Panels, I was also advised to use SIKA 552. This has a greater Tensile Strength than 512, (3N/mm^2 versus 1.8N/mm^2) /and has less stringent surface preparation requirements.

I used it, and so far the panel is still attached!!

I bought the adhesive and primer/cleaner from Amazon. A lot less than £48
 
I'm going to say save yourself some money.. Nothing wrong with sikaflex but there are quite a few other brands of Pu adhesive sealant that will do the job just the same.. I can't remember all the brands I've used over the years but soudal, puraflex are a couple that come to mind....
I'm looking at a tube now of final systems adhesive that I have used for mounting panels..
Just make sure you prep the surfaces by roughing them up a little and making sure they are clean..
And no matter what way you fit the panels its always good to check their security every few months..
Andy..
IMG_20200515_161736.jpg
 
Agree with both the above. I tend to use Tigerseal (a PU adhesive despite the name) because my local motor factor stocks it. As above cleanliness is everything. Plastic needs a good sanding & clean with alcohol to make sure there's no release agent left on it. I've never sanded the roofs that I've done - just scrub with detergent & water then use alcohol.
 
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Are there any specific requirements for fixing aluminium to aluminium ?
What does the activator do ?
Is it just a solvent, would acetone be a suitable substitute ?
I'm planning some brackets for a kayak which will fix to chequer plate
 
as suggested, use spacers to make sure you have a decent bed of adhesive, i used tile spacers on my sat system.

you might want to consider using a black adhesive as opposed to white. it stops it looking grubby and mouldy - it was recommended to me by a member on here and i am more than happy with it, just make sure you clean off any smudges when you have finished.

i used what sikaflex recommended, i am sure there are others just as good but i wanted peace of mind rather than a few quid saved and having used sikaflex before on a previous motorhome, i decided to go with what i knew worked !
 
my honest advice is bin the plastic brackets that came with the panel and buy a length of 50x50 aluminium angle to cut into 150mm lengths. self tapping screws to attach to the panel. bond to the roof with above advice of cleaning and keying the roof plus use of tile spacers to ensure a thick bed of adhesive.

vehicle manufacturers use pu adhesive to bond and seal some panels these days, it is such a strong seal. Sika make several of the cheaper brands too, such as puraflex as sold by toolstation, it is near identical to their own 512
 
TheBig1 said:
my honest advice is bin the plastic brackets that came with the panel and buy a length of 50x50 aluminium angle to cut into 150mm lengths. self tapping screws to attach to the panel. bond to the roof with above advice of cleaning and keying the roof plus use of tile spacers to ensure a thick bed of adhesive.

vehicle manufacturers use pu adhesive to bond and seal some panels these days, it is such a strong seal. Sika make several of the cheaper brands too, such as puraflex as sold by toolstation, it is near identical to their own 512
Click to expand...
Exactly what I do - but without the spacers. I clean the areas of roof where the panel will sit, place it temporarily in position, mask off round each bracket leaving a 3mm margin. Then lift the panel up on temporary blocks so it's a couple of inches clear of the roof. Use a spatula to create a couple of mm thickness of adhesive on the roof in each location, then lower the panel one end at a time into place. The weight of the panel isn't enough to displace much adhesive. Complete with a finger wipe around each bracket then remove the masking tape. I've never bought a panel with brackets provided but I too much prefer aluminium 2 x 2.
 
Revolvor said:
When I contacted SIKA in 2018 asking for advice about fitting Solar Panels, I was also advised to use SIKA 552. This has a greater Tensile Strength than 512, (3N/mm^2 versus 1.8N/mm^2) /and has less stringent surface preparation requirements.

I used it, and so far the panel is still attached!!

I bought the adhesive and primer/cleaner from Amazon. A lot less than £48
Click to expand...

Great advice. Try finding it in whte!
 
Revolvor said:
It's actually made by a company in the Sika group, but has 1/2 the tensile strength of Sika 552 (1.5 N/sq mm VS 3.0 N/sq mm)
Click to expand...
1.5 N/sq mm = 217 lbf/square inch. That means each 6 x 2 bracket requires 2,600 lbf to lift it from the roof. As has been said many times the limitation is the roof rather than the adhesive. If the roof was strong enough with 4 brackets you could lift the entire motorhome. :Eeek:

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Thanks all, just ordered (in White ;-)) should be here tomorrow

Rather have the extra margin of safety and limit amount of holes I put in the roof ;-)
 
Make sure that you clean both surfaces, apply activator and adhesive, as directed, and use tile spacers or similar, to ensure the final adhesive thickness is at least 2 mm.
 

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tonyidle said:
Exactly what I do - but without the spacers. I clean the areas of roof where the panel will sit, place it temporarily in position, mask off round each bracket leaving a 3mm margin. Then lift the panel up on temporary blocks so it's a couple of inches clear of the roof. Use a spatula to create a couple of mm thickness of adhesive on the roof in each location, then lower the panel one end at a time into place. The weight of the panel isn't enough to displace much adhesive. Complete with a finger wipe around each bracket then remove the masking tape. I've never bought a panel with brackets provided but I too much prefer aluminium 2 x 2.
Click to expand...

Sounds like a good procedure. I too, don't like the idea of using spacers because, if too little adhesive is applied, a good mating bond is unlikely to be achieved.

Maybe it's better to initially calculate the amount of adhesive required. For instance, a contact area of 150mm x 50mm x 3mm adhesive thickness would need a volume of approx 22 cubic centimetres. Assuming an extruded bead diameter of 8mm, 6 number beads laid side by side would give the required volume. A little pressure would flatten the beads to the correct thickness. Also, 2 or 3 inspection holes, drilled in the horizontal aluminium would give a good indication of the void being 100% filled when the adhesive squeezed out to the top surface.

This is all a bit theoretical but don't see why it shouldn't work :oops:

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I too used aluminium angle rather than plastic brackets. I remember Techno ( Andy) used to drill and tap a hole in the piece of ally angle, and screw a single pan- head screw into it, so that the head held the bracket away by the requisite 2 mm minimum. The loss of adhesive area is not significant. Search for some very informative threads started/contributed to by him.
 
Revolvor said:
I too used aluminium angle rather than plastic brackets. I remember Techno ( Andy) used to drill and tap a hole in the piece of ally angle, and screw a single pan- head screw into it, so that the head held the bracket away by the requisite 2 mm minimum. The loss of adhesive area is not significant. Search for some very informative threads started/contributed to by him.
Click to expand...
It depends on whether the weight of the attachment and size of attachment points causes much adhesive extrusion. The panels I have mounted (biggest was 250W with 6 mountings) cause very little - just enough to form a fillet with a finger-wipe.

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