T shirt heat press – Common Questions

This is a short guide to answer some very common questions when it comes specifically to t shirt heat presses, that is – heat transfer presses that are to be used predominantly for decorating T shirts. If you want to read a much more in depth guide, see our heat press guide

Clamshell presses make for good T shirt heat presses, and the Stahls clam basic presses, and the Hotronix Auto open presses are particularly popular transfer presses for Tshirts. There are of course also swing presses, and the first question people have when setting out to print Tshirts is often whether to go for a clam or a swing press. 

Clamshell heat presses open directly upwards as a sea shell would, hence their name, while swing presses work by the top platen lifting up vertically, remaining parallel to the bottom table, and then swinging out of the way. 

To get an idea of the difference:

Clam or swing away heat press

To replicate the way a clamshell press works, put your palms together and then open your hands, and close them again – this gives you a rough idea. To replicate a swing press, put one hand on top of the other, lift your top hand up about an inch while keeping it parallel with the bottom hand, and then turn the top hand around towards the back so your fingers are pointing the opposite way to the fingers of the opposite hand. 

ricoh 3110 clam basic sublimation printing setupLooking for a complete dye sublimation printing setup


What you’ll notice straight away when you do this, is that a clam press wouldn’t be able to press items as thick as a swing press, as you’ll notice your hands are only parallel when they’re very close together, and it’s similar with clamshell presses. You’ll also notice that the footprint of the clamshell press is all you will need in terms of space, but with a swing press you’ll see that you will need space all around the side and rear of the press to swing the platen. 

Clamshell Press Pros:

Space saving. Clams are good in terms of not taking up much space, as they open vertically so you don’t need to worry about the space around the press and behind it. 

Fast operating. It’s just a case of opening, closing, removing the garment and dressing the platen again with the next garment. This is particularly true with Auto open presses, as you can get straight in there to remove the garment without even having to lift the top platen.

Ease of use: There isn’t much physical effort involved other than closing and opening the press, and one you have relieved the pressure, most clamshell presses will open with little or no effort required.

Price: Generally speaking clamshells are less expensive to manufacture, and less expensive to buy.

Our most popular clamshell Tshirt presses are Stahls Clam Basic, Hotronix Auto Open, and Geo Knight DK16 & DK20

Clamshell Press Cons: 

Heat towards bottom table. When the top platen is raised, it is directed towards the bottom table. If you’re needing to do any fiddly processes on the bottom table, it means doing so while heat is being directed towards your hands, and towards the transfer media.

For processes where you would be required to carry out fiddly weeding or peeling while the Tshirt is still on the press, having a swing away press may be more appropriate as the heat platen can be swung out of the way.

Pressure. Some (not all) clamshell presses do a fairly ineffective job when it comes to the amount of pressure generated, and the distribution of pressure across the platen.

When it comes to dye sublimation for example, this wouldn’t usually cause any problems, however with certain heat transfer processes including laser transfer, pressure is very important. For this reason, clamshell heat presses aren’t as popular for processes such as this which require particularly heavy and evenly distributed pressure.

Substrate thickness. As mentioned earlier, clamshell presses can’t usually take items as thick as swing presses can. Tshirts and hoodies etc., would usually be fine with a clam press, but if you wanted to press onto wooden plaques, acrylic blocks or other thicker items, you may need a swing press. 

Swing Press Pros & Cons.

The pros and cons for swing presses are the polar opposites of the pros and cons listed for swing presses. Swing presses are not as good when it comes to space saving due to requiring the space all around and behind the press to swing the top platen.

They’re generally better when it comes to pressure capabilities, they usually take thicker items / substrates than clams, and they are better for processes which require you to work on the bottom table, as the heat platen isn’t pointing directly towards the bottom table while you’re working on it.

They generally ever so slightly slower to operate, and take slightly more operator effort, as you have to release the pressure and then swing the head, rather than just releasing the pressure and then letting the press open, as with a clam. 

Swing presses are usually more expensive, as they usually cost more to manufacture.

So if you weren’t before, you’re now fully clued up on the difference between swing presses and clamshell presses.

Our most popular swing presses are Geo Knight DK20S, DK20SP, and the Hotronix Fusion press, which is a dual motion swing head and drawer press.

What does threading mean

Threading refers to dressing a Tshirt or other item, onto the bottom table of your press. You could just lay your Tshirt onto the bottom table, in which case you’re not threading it – if you were to actually dress the tshirt or hoodie etc onto the bottom table so that one side is on the lower table and the other side is around and under it, then this is a threaded garment. 

Being able to thread a garment onto a heat press can be a plus for a few reasons. It means that the inside of the front of the shirt is on the lower table, and if there is anything on the lower table which may put a slight mark onto the garment, then it’s less of an issue if this happens on the inside of the front, than if it were to mark onto the outside of the back of the garment. It can also make it easier to align your transfers, and to avoid getting wrinkles or creases in the garment which could ruin the transfer. 

Cheap Presses Vs Higher Quality Heat Presses.

The next question many ask is whether they should go for a cheap tshirt heat press on eBay or another auction site, or to invest more in a branded press, and this is a common question. 

The cheapest heat press we offer are the Stahls clam basic, they’re a decent press at the lower end of the price range, made by a very well established and trusted name in heat press technology, Stahls USA, and they’re sold with a solid 12 month warranty.  

The difference between these and the higher priced presses we offer simply comes down to the cost of the parts used, and is reflected in the length of the warranty, for instance clam basic have a 12 month warranty, Hotronix Auto open have 5 years on the framework, 2 years on the digital controller & lifetime on the element.

In terms of what impact the quality of your heat press will have on the quality of the finished T shirt or whatever it is you are producing, this really depends on the process you are using, and how forgiving a process it is when it comes to the pressing. Dye sublimation for instance is much more forgiving a process when it comes to pressing, than laser transfer, which usually requires a heavy pressure, and even heat and pressure distribution across the platen.

But just as important as the quality of the finished product, is the reliability of your heat press to keep you producing Tshirts or whatever it is that you’re planning using your heat press to produce. A saving of a two or three hundred pound may seem like a lot,  but once you’re up to full production speed, how long without a working heat press would it take for your lost of earnings to overtake such a figure?

Heat press manufacturers who have been around for quite some time, and have invested a lot in building their brand, work hard to ensure that the machinery they are manufacturing, and their after sales service, are doing justice to that brand.

Compare the above scenario to the several factories in China, Taiwan and other countries who manufacture large quantities of low cost heat press machines, being sold via several different agents and re-sellers across several countries. The main difference is you’re not buying into a trusted brand, so it all boils down to how well you trust the re-seller. 

If you buy a well known brand of any type of machinery, you can usually get support directly from the manufacturer even if for some reason you’re unable to get help from the supplier. If you purchase a none branded imported press, you’ll find it difficult if not impossible to even find out who the manufacturer is, let alone get support from them.

Many of the cheap heat presses being sold via eBay and other websites, are actually being shipped directly from the country of origin, even if they mislead you to think that it’s UK stock.  If you buy a press from a supplier like this, and you go back to them when you have a problem, you may discover that they don’t stock any parts for the machine, so these need to come from China for instance, which means waiting.

In some cases the buyer has discovered that their press needs to be sent back to the country of origin, and even that they are expected to pay for this… 

We hear horror stories like this occasionally from customers who are making the decision in hindsight to invest in a known brand, having suffered the potential consequences of buying purely based on price the first time round, and not wanting to repeat the mistake.

CE mark.

As was mentioned earlier, some of the heat presses available, even some that state they’re UK stock, are actually being sent directly from China or wherever they are being manufactured.  

They will usually state that they’re CE marked, but having a sticker on them doesn’t make them CE approved, there has to be paperwork to back this up, and we know from experience having once challenged a Chinese supplier on a CE mark, that you can not always assume that there is actually the paperwork to back up a CE mark. 

While initially this may not be an issue, it would become a potentially very big issue if there were to be an issue with the heat press which lead to an insurance claim, if the insurance company investigated and found that the machinery in question was not actually CE tested and approved.

If you’re purchasing via a well established and trusted UK based supplier, then you would assume that the supplier would have ensured that the machinery they’re supplying is indeed CE marked.  

The End

Of this short guide – but it may just be the beginning of your quest for heat press knowledge ;-). If you have further questions, see our heat press guide, and if you have any specific question just drop us an email, support at subli.co.uk, or give us a call on 01625 876 949.

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