Rebedding in the rain?

[poopdeckpappy]

First I need to correct what I said, I said it was not very flexible when I meant to say it is very flexible


Second

Originally Posted by Maine Sail

Please lets not confuse Thiokol based Polysulfides with Polyurethanes!!!

I made no such error

First polysulfides are not generally considered in the "adhesive sealant" category

Generally ?? maybe, but not 100% true, what I was referring to was a polysulfide adhesive/sealant that is very flexible and dose have a bonding strength of 1000psi ( yes, over kill, but none the less ) and it is safe to use with most plastics, ( Synthetic glass & PVC don't fall into the compatible materials) but is compatible with most all other Plastics found on a boat ( ABS,Epoxy, Nylon, etc: )

and secondly there is no commercially available polysulfide product that comes even close to 1000 PSI.

yes there is and yes it is commercially available,




You know the original author of this topic said nothing about bedding plastic, that is, like I said, his boat was built by Revell and his Chain plates and stanchions are made of Lexan,Plexi or PVC, So the 'suggestion' of BoatLife Lifecaulk was a good suggestion, as were all the others.

Bottom line is know your material and know your product

Oh and your list of caulking products is short by several thousand adhesive/sealant products

[Maine Sail]

Originally Posted by poopdeckpappy

First I need to correct what I said, I said it was not very flexible when I meant to say it is very flexible


Second


I made no such error

Sorry thought you did and with the bad "shoot from the hip" info thrown around these days I wrongly assumed. My bad and I own it!!

Originally Posted by poopdeckpappy

Generally ?? maybe, but not 100% true, what I was referring to was a polysulfide adhesive/sealant that is very flexible and dose have a bonding strength of 1000psi ( yes, over kill, but none the less ) and it is safe to use with most plastics, ( Synthetic glass & PVC don't fall into the compatible materials) but is compatible with most all other Plastics found on a boat ( ABS,Epoxy, Nylon, etc: )

yes there is and yes it is commercially available,

I would really appreciate it if you could steer us all to a more highly adhesive polysulfide suitable for use in the marine environment that is also bellow waterline rated and has 1000 PSI adhesion?

I think many would be interested in this product!

Originally Posted by poopdeckpappy

You know the original author of this topic said nothing about bedding plastic,

I am fully aware of that! I mentioned after dog to reiterate a good point. I've worked in three different boat yards and have seen MANY products from portlights to inclinometers ruined by Life-Caulk/Polysulfide. I love polysulfide it is my sealant of choice next to butyl but you need to understand when and whre to use it that's all.

Originally Posted by poopdeckpappy

that is, like I said, his boat was built by Revell and his Chain plates and stanchions are made of Lexan,Plexi or PVC, So the 'suggestion' of BoatLife Lifecaulk was a good suggestion, as were all the others.

Yes Life-Calk or 3M 101 would both eb great choices..

Originally Posted by poopdeckpappy

Bottom line is know your material and know your product

Oh and your list of caulking products is short by several thousand adhesive/sealant products

I do know my sealants fairly well, at least the marine rated ones. No commercial boat yard I have ever worked in would ever consider using a non marine or non-bellow waterline rated product. While there may be better products out there the insurace companies would have a field day if a boat sunk because a boat yard used a construction trade sealant not specifically rated so they usually don't.

Of course my list is short and I tried to keep it succinct to what you may find in a marine chandlery . I did not mention any of the boat builder/ marine trade specific stuff such as Plexus because they are hard to find and especially in small volumes & no one on this forum wants to buy a 55 gallon drum..


Sorry for thinking you were confusing polysulfides with polyurethanes! We would all like to know about this commercially available 1000 PSI polysulfide product..?

[poopdeckpappy]

MS, I did not intended to be disrespectful to you or SD, I hold SD & your knowledge of such things in high regard.


Master Bond is manufactured in Hackensack, New Jersey and you buy direct though them.

They have 2 polysulfades adhersive/sealants that I know of ( maybe more ) that are rated for marine use along with auto & aerospace

One is EP21TP-2 and the other is EP21TPFL-1, neither of these could be found at the local chandlery on a Saturday morning but, if your project is planned in advance and you want to use the best possible products, they can be had.

Also, if the consumer does not know what to use, he/she could call them, tell them what you're doing, with what material(s), in what environment and they will tell you the best product to use

[poopdeckpappy]

Master Bond Products by Type


I stumbled across them though my work in the construction industry and goofing with offroad vehicles , not that this means anything, it's just how I found them

[Maine Sail]

Now I understand why they have a 1000 PSI rating. It's not solely a Polysulfide but rather a Polysulfide/epoxy hybrid mix with added epoxy.

The added epoxy is clearly where it gets it's 1000 PSI rating from. I'd like to see some elongation before break numbers but they don't give the data on the site. Have you asked them about elongation before break numbers??

It does seem a little too permanent for bedding and with the epoxy I would not guess it can match the flexibility of a straight Polysulfide but you never know. 3M 101 is roughly 416% elongation before break..

[poopdeckpappy]

EP21TPFL-1fficeffice" />>>	> >
> >	> >
Substrate Compatibility >>	CeramicGlass; ConcreteMasonry; Metal; Plastic; Porous Surfaces; Rubber or Elastomer; Wood; Dissimilar Substrates; Metal/Plastic/Glass/Ceramic/Elast.&Wood >>
Industry >>	Aerospace; Automotive; Electronics; Electrical Power or High Voltage; Marine; Military; OEM or Industrial; Semiconductors or IC Packaging; Chemical/Oil Processing/Metal Working >>
Material Properties (Nominal / Typical) >>	>>
Process & Physical >>	> >
Viscosity (cP) >>	> >
Gap Fill (inch) >>	> >
Thermal >>	> >
Use Temperature (F) >>	-65 to 250 >>
Thermal Conductivity (W/m-K) >>	0.2880 to 0.4320 >>
CTE (µin/in-F) >>	39 to 50 >>
Mechanical >>	> >
Tensile (Break) (psi) >>	250 to 270 >>
Elongation (%) >>	230.0 >>
Electrical >>	> >
Resistivity (ohm-cm) >>	1.00E12 >>
Dielectric Strength (kV/in) >>	360 to 450 >>
Dielectric Constant >>	6.80 >>
Optical >>	> >
Index of Refraction >>	> >
Transmission (%) >>	>>
> > >> EP21TP-2>>	>>
Substrate Compatibility >>	CeramicGlass; ConcreteMasonry; Metal; Plastic; Porous Surfaces; Rubber or Elastomer; Wood; Dissimilar Substrates; Metal/Plastic/Glass/Ceramic/Elast.&Wood >>
Industry >>	Aerospace; Automotive; Electronics; Electrical Power or High Voltage; Marine; Military; OEM or Industrial; Semiconductors or IC Packaging; Chemical/Oil Processing/Metal Working >>
Material Properties (Nominal / Typical) >>	>>
Process & Physical >>	> >
Viscosity (cP) >>	5000 to 6000 >>
Gap Fill (inch) >>	> >
Thermal >>	> >
Use Temperature (F) >>	-100 to 300 >>
Thermal Conductivity (W/m-K) >>	0.2880 to 0.4320 >>
CTE (µin/in-F) >>	39 to 50 >>
Mechanical >>	> >
Tensile (Break) (psi) >>	> >
Elongation (%) >>	50.0 >>
Electrical >>	> >
Resistivity (ohm-cm) >>	1.00E12 >>
Dielectric Strength (kV/in) >>	360 to 450 >>
Dielectric Constant >>	4.00 >>
Optical >>	> >
Index of Refraction >>	> >
Transmission (%) >>	>>

>>

[poopdeckpappy]

Does any of the above help ??

tensile break is 1000psi, and elongation (%) is 50 for EP21TP-2

tensile break is 250-270psi and elongation(%) is 230 for EP21TPFL-1

[poopdeckpappy]

Here's a similar/dissimilar substrat chart


http://www.masterbond.com/sg/masterbond_substrat.pdf

[Maine Sail]

yes and I clearly could not find that data on the site. Polysulfides generally have lower elongation at break than do polyurethanes. 3M 101 Polysulfide is half as flexible as 5200 at 416% but even the best of this stuff is half of 3M 101 Polysulfide. 50% elongation before break is not enough IMHO on boat for bedding stanchions or chain plates. I have seen the stainless steel plate on some stanchions flex as much as 1/16" of an inch. If you have a 1/32" layer of sealant 50% does not satisfy this type of flex and it will likely fail. My bottom number that I'm comfortable with is around 300-350%.

I'd love to find a polysulfide with 600-800% elongation before break but that still had a low 140 PSI adhesion!! The only draw back to polysulfides is their restricted, compared to polyurethanes, elongation before break.

Thanks for that data..!

[poopdeckpappy]

You bet, thanks for your opinion on that data


Question, if you used a adhesive/sealant with a 1000psi break point on stanchions or chain plates that where also though bolted, why would the elasticity be a factory