Unshrink/Stretch Canvas?

[Jmreim]

We have opaque canvas covers on the inside of the windows in our pilothouse - they’re attached with snaps at each corner or angle change so there are 4-6 snaps per cover. Sadly, we washed them over the winter (cold water and hung to dry) - when we tried reinstalling today, they’d shrunk significantly (about 1” short in all directions). Someone suggested soaking them for 30 mins in a mixture of (warm?) water and hair conditioner), wringing them out as best we can and then attempting to stretch/snap them in place to dry. Anyone had this issue and successfully re-stretched canvas to fit or is this a futile effort?

 

[Comodave]

That is likely your best bet. Although there are some snap extenders you can buy to help it fit. Look a bit cheesy though IMO.

 

[SteveK]

warm water, hmm, only have used cold, will have to try that as it sounds better.

 

[Jmreim]

so you've had this issue, Steve? Did the cold water work to stretch the fabric back to original size?

 

[Bmarler]

There are tools that are good to have when you need to stretch the canvas a little to install it.
https://www.sailrite.com/Top-Snapper-Tool

 

[Senojev]

Try This Approach

I have not tried this on canvas but have on wool sweaters that have shrunk. My wife who is a weaver gave me this tip.

Mix up a VERY strong solution of fabric softener in lukewarm water and agitate thoroughly. Let sit overnight and agitate again. Rinse thoroughly in cold water and find some way to stretch the fabric out while it dries. The theory is that the yarn tightens up by twisting more tightly when washed initially resulting in shrinkage. The fabric softener lubricates the yarn and allows it relax back to it original twist.

 

[SteveK]

so you've had this issue, Steve? Did the cold water work to stretch the fabric back to original size?

Yes I have, on a winch cover and windshield cover.
Both now fit until they shrink again.

 

[garbler]

My only question is are these covers really canvas or canvas duck or synthetic blend. True cotton canvas usually shrinks the most along the warp so you’ll need to factor this. I laid canvas decks for a few years and of course we relied entirely on controlled shrinkage to yield a smooth tight deck.

Rick

 

[SteveK]

My only question is are these covers really canvas or canvas duck or synthetic blend. True cotton canvas usually shrinks the most along the warp so you’ll need to factor this. I laid canvas decks for a few years and of course we relied entirely on controlled shrinkage to yield a smooth tight deck.

Rick

Does it matter? If it once fit, snaps as proof, then it shrunk and can be stretched back (unless it rips due to age).
Actually, I never thought of any "canvas" on the boat to be cotton, always thought synthetic.

 

[Jmreim]

Canvas Shrinkage

Not certain what the material actually is but we've bought canvas at a material store recently that looks exactly the same. I've attached an image of the shrunken window cover below and a friend noticed that the entire perimeter appears to be puckered (shrunken), while the rest of the cover seems to be fairly relaxed. He speculated that perhaps it was the thread used on the foldover that has shrunken the most, not the rest of the cover

.

 

[garbler]

Does it matter? If it once fit, snaps as proof, then it shrunk and can be stretched back (unless it rips due to age).
Actually, I never thought of any "canvas" on the boat to be cotton, always thought synthetic.

Okay I understand, you don’t know what canvas is. That today everything is plastic. Anyway from the museum of materials history we find that different fabrics act differently and therefore must be applied or used differently. Wow !
Wonder if sailmakers know this

Rick

 

[SteveK]

Okay I understand, you don’t know what canvas is. That today everything is plastic. Anyway from the museum of materials history we find that different fabrics act differently and therefore must be applied or used differently. Wow !
Wonder if sailmakers know this

Rick

Guess the one I used did not since they don't have a cotton sail. Still call it canvas, hope you can live with that.

 

[C lectric]

I use that Top Snapper Tool for my back deck Sunbrella cover. I didn't say canvas.

It makes a huge difference in the fighting to get the cover to fit the snaps. By hand alone it is an impossible task. With that Snapper if becomes a lot easier and doable.
Once in place and stretched if become easier each time although it is still tight.

 

[STB]

Are you sure it is the washing thst is making it hard to fit, not the temperature?

I don't have a good mental model for why, but both with my boat's and with my canvas truck bed camper top, I have noticed that they are /much/ harder to manage in the cold. I can't get the camper top assembled in the cold of winter, and even in a Los Angeles winter I had a lot of trouble with my boat canvas. In Florida I have noticed it is tighter in the winter, but not nearly so much.

I see you are in Maryland, so I'm betting something that went on nicely in July would be really hard on a cold winter or early spring day.

To be clear, if my boat or truck canvas was still on in the winter from earlier in the year, it was just fine. It was just welhwn taken off that it became a.problem.to put back.

Given this my model would be to wait it out or to work in the sun on a hot day and to heat it to 95 Fin a large tub of hot water and to try to put it on real quick, puking out only one po3ce at a time.

 

[Jmreim]

I’m not really sure of anything. It was <40F in the pilothouse today when we attempted to put the covers back on. We made the attribution to washing b/c we were >1” short of the snaps all around - that seems excessive and the covers had been stored in our warm house before being transported to the boat in our modestly warm car.

 

[C lectric]

My experience. Any fabric like this shrinks and with fixed anchor points they need to be stretched. Once gotten into place they will stretch almost back into place.
If the anchor points are floating then likely not a big deal.

 

[SIBERNUT]

You should look at the material used to edge it. Many shops will use a vinyl edging on white instead of the same material the cover is made from. LOTS cheaper. But the vinyl shrinks with age unlike the cover itself, and removing it allows the cover to return to shape. Someone mentioned Maryland, I'm in Middle River & will help if you are close.

 

[Caballero II]

We have opaque canvas covers on the inside of the windows in our pilothouse - they’re attached with snaps at each corner or angle change so there are 4-6 snaps per cover. Sadly, we washed them over the winter (cold water and hung to dry) - when we tried reinstalling today, they’d shrunk significantly (about 1” short in all directions). Someone suggested soaking them for 30 mins in a mixture of (warm?) water and hair conditioner), wringing them out as best we can and then attempting to stretch/snap them in place to dry. Anyone had this issue and successfully re-stretched canvas to fit or is this a futile effort?

The snap extensions are about 1", and work wonderfully. I don't think they look "cheesy" but look like an actually professional solution to shrinkage. They are leather and will easily solve the solution in the short-term. If you don't like them, then you can follow the other advice here about "relaxing" your canvas. I, rightly or wrongly, have accepted shrinkage as inevitable and added these. I think they look fine, and do the job. Sailright.

 

[Bmarler]

You should look at the material used to edge it. Many shops will use a vinyl edging on white instead of the same material the cover is made from. LOTS cheaper. But the vinyl shrinks with age unlike the cover itself, and removing it allows the cover to return to shape. Someone mentioned Maryland, I'm in Middle River & will help if you are close.

Wouldn’t you use bias tape for edging? Either bought or self made it seems like the proper way.

 

[Bacchus]

I’m not really sure of anything. It was <40F in the pilothouse today when we attempted to put the covers back on. We made the attribution to washing b/c we were >1” short of the snaps all around - that seems excessive and the covers had been stored in our warm house before being transported to the boat in our modestly warm car.

By any chance did you put them in a dryer after washing?
Excessive heat will shrink acrylic fabrics (Sunbrella & some others) I think polyester is similar. I don't think there is any easy way to reverse heat shrinkage.
I found Sunbrella boat covers more difficult to reinstall and snap after washing and agree with the comments that it's easier in warm temps than when cold.

Looking at the photo it appears the panel is "self edged".... no separate edge material used but rather the panel is over sized and folded in 2X to hide the raw edge inside the "hem". That is a relatively easy DIY fabrication job and if so inclined you might consider DIY replacement. Having the ability to DIY some "canvas" projects for boats is a real advantage. It really is not rocket science... especially starting w fairly simple flat panels like these.

 

[Cigatoo]

What STB said. Not sure what the temp was when you tried to install? However if it wasn’t sunny and 70 wait til you get a day like that. Let the canvas soak up some heat while hanging in place. It will go on just fine. Been there done that almost every spring. My canvas is not as tight as I would like it however it still won’t fit at 50 degrees. 70 degrees it goes right on.

 

[Pete Meisinger]

It might be to late for my suggestion but..

I had my mooring cover made with twist lock fasteners. Much easier to use with arthritic hands and more sturdy.You might be able to convert your window covers to these, they will continue to shrink, no matter what you do.

pete

 

[SIBERNUT]

Yeah, the twist locks are nice but expensive, and to do it neatly you need a punch for the oval hole. The "Top Snapper" works well, and can be used all over the boat. They run $25 or cheaper on Ebay. Chap-Stick works well as a lube (& zippers too).
As a note on the snaps- see if your inner part spins. If it does, it's ready to pull out. Re-press them either with a REAL tool or maybe a center punch. I loan tools to my customers frequently. Or, you can buy a "Press-n-Snap" for maybe buck & a quarter

 

[Marco Flamingo]

Although I have the equipment, material, experience, and equipment to simply sew new covers, if it were my project I would go with fabricating snap extentions. Even a cheapo snap fastener would be good enough for this project. Buy one that comes with snaps or make sure that the snaps are standard enough so that you can buy enough at the same time. Probably $50 for fastener and fastenings for all the shrunken canvas on the boat. Then get a couple yards of 3/4 inch nylon webbing that matches the cover color. Cut your own extention pieces to whatever length you need. Seal the cut ends with a BIC lighter. "Punch" the holes for a snap using a leather punch (another $10). You can make 100 custom extensions (make extras). It sounds time consuming, but it will be a big time saver over soaking in fabric softener, stretching, and finding that doesn't work. Or trying to alter the shrunken material, and finding that doesn't work. And you will have the equipment to fix snaps in the future.