Seam sealing weight gain?

[Anonymous]

I bought a new tent and paid to have my it seam sealed by the manufacturer and was expecting it to add a couple ounces max to final weight but weight with stakes came out to +4.5oz over the stated unsealed specs with stakes. I will not go into specifics on the tent/manufacturer but it is a roomy one person tent. Does this seem like a lot of variance even with seam sealing? Thanks.

[Bob Gross]

The stakes alone could add a few ounces to the bare tent weight.

The amount of seam sealer applied might be a few ounces, but a lot of that weight is in the solvents that will evaporate over a day or two. I would expect maybe one ounce to remain, but that depends on exactly what kind of goop they are using.

Further, there is generally a certain amount of natural weight variation on a new tent, at least a few percent.

–B.G.–

[J R]

So the seam sealant is the only difference between what you are weighing and the manufacturer's stated weight? In other words, stakes are either on both sides of the equation or neither side? Guy lines? Etc.

I wouldn't expect the finished tent to vary from spec by more than an ounce, so you're still looking for 3.5 ounces. For comparison, a tube of Sil-Net holds 1.5 oz (by weight), so more than two tubes of goo to seal a 1-person tent? Sounds high to me.

Other possibility: sure your scale is calibrated?

[Jerry Adams]

and most of the weight of the tube of seam sealer evaporates. Maybe seam sealer adds 1 ounce?

weight of your particular tent might be a few ounces greater than spec

[Greg Mihalik]

From my experience, sealer amounts to around an ounce or less.

I'd guess that the tent was over spec to start with, and that is not uncommon.

On one purchase (5 years ago) where I was being particularly anal, I had the vendor look for the lightest one in stock. The variations were surprising. He attributed them to the silicone coating.

[Anonymous]

Yes the only variable is the seam sealer.. the advertised weight includes everything the tent comes with including stakes, stuff sack, guylines, etc.

to put it in perspective, the seam sealed version (with all accessories) is 13.6% more weight than the unsealed specs (with all accessories). My scale is calibrated correctly, this is the only item in my entire backpack that seems out of whack vs manufacturer specs.

[A J]

Sent you a PM.

[Anonymous]

Ok so I have found out where the discrepancy is coming from. The tent is a Tarptent Stratospire 1, on the product page it says it ships with 6" stakes but they were actually shipped with 8", so that adds on 0.9oz

Also, it seems that the weight on the tarptent webpage may not have been updated since they updated their fabric 2 years ago to shield silnylon? see this thread: http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=86780

Not sure if there is an updated weight for the stratospire since it has always been shown as 33oz as far as I know?

so between the longer stakes, different fabric and seam sealing this is the 4.5oz. If this is the case then I think tarptent's webpage should be updated. The weight for the stratospire shipped unsealed is probably closer to 36oz.

So is the weight for the Notch accurate or what? If it is then the weight difference between the two just jumped from 7oz to 10oz, which is only a few ounces, but still, I would have thought longer and harder about the Notch if this is the case.

[J Dos]

Hey Aaron, I just received a brand new seam-sealed Tarptent Notch last week. With everything included (4 6" stakes, full mesh interior, tarp, guylines, stuff sack, seam sealer) the total weight came to 27.49 ounces on my scale. That's spot on with what Henry advertises on his website.

[Franco Darioli]

They do change a bit in weight.
The weight given on the TT website is the one with the mesh inner.
Add a fe oz for the solid (fabric) inner.

[Anonymous]

Franco, mine is with the mesh inner. At the very least the website needs to be updated to say that it comes with the 8" stakes which adds almost a full ounce to the stated weight. Still leaves 3.6oz unaccounted for.. call it 1.6 for seam sealer, still leaves an extra 2oz.

[Anonymous]

From Henry:

"Yes, I think the seam-sealing estimate sounds about right. We did “upgrade” the stakes package from 6” to 8 3/4” and that adds another ounce. Anything beyond that is just fabric weight variances due to increased coatings over the last couple of years. Fabrics we use now are much better/more waterproof than from a couple of years ago but that’s the tradeoff.

You are welcome to send it back if it doesn’t meet your needs. I will say that no one can tell the difference of a few ounces in a loaded pack. No body. Try it yourself—do a “blind” test—and prove it to yourself.

Thanks."

Take his email how you want, but it sounds like to me the fabric has been changed years ago and ships with 8" stakes, none of which are updated on his website and add around 3oz to the state weight. Merely pointing this out to people doing research, I plan to keep this tent.

[Eric Blumensaadt]

Aaron, methinks you're takin' this here SUL thing a wee bit too much to heart.

>Yer b**gers will weigh more than the seam sealer.
>Yer earwax will weight as much as the seam sealer.
>Yer toejam and uncut toenails will weight as much.

Don't sweat the small stuff.

[b willi jones]

methinks the o.p is right to sweat the small stuff. the company he purchased from is selling goods that they know are not correct to the advertised product, and they apparently are not doing anything to update it… to me, that is wrong and misleading. i dont own any of their products, but im sure this company is better than that…

[J R]

Suppose the OP sold his former equipment, at a loss, so that he could shell out big bucks to get a new shelter for the purpose of saving himself a few ounces, only to find that he didn't save the weight he expected and is told by the manufacturer, in effect, to suck it up. That sounds like a mix of false advertising and arrogance to me.

To get into SUL territory is a game of shaving ounces. Reducing base weight from, say, 13 lbs to 10 lbs is a matter of scrutinizing, and usually paying for, each ounce and gram to get there. Will any one extra ounce be felt on your back? No. But how will you ever get there if the ounces saved are phantom ounces? It all adds up.

No manufacturer should knowingly advertise false specs and then dismiss the difference after the fact as something the customer is just whining about. Breach of faith, breach of promise.

[Anonymous]

Eric, if I sweated the small stuff I would say I am returning the tent and not buying from them anymore, but I said I was keeping the tent. They obviously make quality gear and I am willing to take the weight penalty, just not happy about it. I just think that in the lightweight backpacking world, ounces count. I also think that when you shell out hundreds of dollars for something you should get what the description says it is. Its a matter of making the most informed decision possible. I see numerous discussions on here about shaving weight, I even made the point that there is a multiple page thread on here on a trowel (< 1oz) vs a shoe vs a stick! I mean you cant tell me 3oz don't matter to people.

I merely asked them to advertise accurate specs and I put this on the board so people would have more information to make a better decision should someone be in the market for this tent vs another.

[Jerry Adams]

You won't notice a pack that weighs 1 or 3 ounces less.

If you can combine 1 or 3 ounces savings with some other savings to add up to a pound or more, then you'll start noticing it.

[Anonymous]

I guess that makes it ok for ALL manufacturers to post weights 9% under the actuals.

Add 9% onto everything in your pack, tell me that wont make a difference.

For me this is a matter of ethics, not a matter of ounces. Clearly from the email they are well aware the tent ships at a higher weight.

[David Drake]

"A matter of ethics," is pretty strong stuff, Aaron.

By your own figures, you're talking about an increase due to fabric weight of 2-3 oz, or 6-9%. People who make their own gear (as I do) would say that's not far out of line from expected variation between one lot of fabric and another. And in this case, the (very slightly) increased weight translates to increased performance.

I have no relationship with TarpTent (don't even own one) but it seems they are the best known of the cottage products outside our little gram-counting community. I suspect most of Henry's customers care more about a tent that doesn't leak (or "mist") with stakes that hold, than minor variations from published weight. Me, I take *all* manufacturer's specs as estimates–+/- 10% is no big deal.

You ask if 9% increase for everything in my pack would make a difference? These days, my three-season BW is about 7#. So no, a 9% increase wouldn't really be noticeable, except on my spreadsheet. In fact, I recently increased my pad weight by about 45%, for the increased performance of a better night's sleep.

Your choice of shelter and the sleep systems and backpacks you've considered on other threads make it clear weight isn't your top priority. If you wanted it, a different shelter could easily save a pound vs. the Stratospire.

[Ryan Smith]

Aaron,

BPL has had this conversation a few times before. It always falls into the "care vs don't care" debate as this thread has. Myself- I care. Dishonest? Unethical? I dont want to speculate on the motives, but at the very least its poor QC. So, I buy from those manufactures who can quote accurate specs.

Example: Just bought a Zpacks bag that was spec'd to weigh 25.8oz. When I weighed it – You guessed it 25.84oz.

Ryan

[David Ure]

I am with Greg – one really can't determine how much the seams sealing added in weight because the shelter wasn't weighted first without the seam sealing completed.

My experience is as follows:

-1.3 oz added to an MLD DuoMid.

-1.8 oz added to a Tarptent Notch.

[David Drake]

I'm not a textiles expert, Ryan, but your example may be apples/oranges. I suspect the weight of shell fabrics for bags (or Cuben, in the case of zPacks shelters) is far more predictable from lot to lot than silnylon. And the high cost of good down creates an incentive to keep fill weights spot-on.

Greg's post above makes it clear there's significant variation from one tent to another within same style and same manufacturer. That's not going to be a variation in fabric area, and it's hard to see why a manufacturer would use random lengths for guy lines, tie outs, etc. How should a manufacturer quote 'accurate' specs when this is the case?

Going to Shield silnylon is generally regarded as an *increase* in quality. Maybe there's a slight weight penalty for that.

But for gear *outside* the SUL realm (and prob. even within it) the debate seems a little silly and/or dogmatic.

(edit for clarity)

[A J]

Yes, while no one will notice +3 ounces, it seems that the manufacturer knows they are using heavier materials, but have not updated their website to reflect this.

While no one would notice 3 ounces, if you are deciding between a 20 ounce tent and a 24 ounce tent, that 24 ounce tent now becomes 27 ounces. You may have told yourself that you wouldn't notice a 4 ounce difference, but now that difference is 7 ounces.

It would be completely fine if the manufacturer just indicated they are using a higher grade silnylon (which is an upgrade in my book, even if there's a weight penalty). The fact that it's not disclosed creates an issue when people cannot accurately compare tents across manufacturers.

[David Drake]

*What* should be disclosed?

Thru-Hiker sells Shield brand silnylon, and lists weight 1.1oz/sq yard base fabric, 1.4 oz./sq. yard after coating. DIYGearSupply sells a less expensive (presumably 'generic') silnylon, also 1.1 oz/sq. yard base, and "~1.4 oz/sq. yard" after coating. So on paper (on screen?) both the best silnylon and the average stuff are the same weight.

Thing is, I doubt any silnylon is the result of a super-precise manufacturing process, viz. all the silnylon 2ds that are available (some of which have weights after coating as high as 2 oz/sq. yard). There is going to be unavoidable weight difference from lot to lot of material (even the same brand), which means tent-to-tent variations for cottage makers that produce any appreciable number of tents. I assume makers deal with this by stating an average weight based on some batch larger than 1, but less than 100. How often should they re-average their stats?

I suspect most folks who've played the spreadsheet game for a while know all this, and take stated weights as ballpark. Weights across manufacturers, even more so.

[J R]

Taking at face value the letter from the manufacturer that Aaron presented, the manufacturer knew of discrepancies. So what should be disclosed? That which is known to be a discrepancy — stakes and materials with different coatings that are heavier than advertised — would be a good start. That isn't a variance, that a non-disclosed change in specs. Whether it provides the buyer with higher quality at a small weight penalty could be a great thing, but that is for the buyer to decide and should be fully disclosed, wouldn't you agree?

Let's turn it around — why would a manufacturer knowingly maintain the *wrong* product specs on their website? Not any good reason. And BTW also not in compliance with FTC standards (yes this isn't just a matter of opinion or ethics but of law as well).

[Author]

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